MEDICAL    SCHOOL 


COLLEGE  OF  PHARMACY 


of  Pharmacy 


PROGEESSIVE  PROBLEMS 


GENERAL  CHEMISTRY 


BY 
CHARLES   BASKERVILLE,  PH.D. 

PROFESSOR    OF    CHEMISTRY 
AND 

W.  L.  ESTABROOKE,  Pn.D. 

INSTRUCTOR    IN    CHEMISTRY 

COLLEGE  OF  THE  CITY  OF  NEW  YORK 


College  of  Pharmacy 


REVISED 


D.   C.   HEATH   &   CO.,   PUBLISHERS 
BOSTON        NEW  YORK        CHICAGO 


COPYRIGHT,  1910, 
BY  D.  C.  HEATH  &  Co. 

2B  O 


PREFACE 

THE  application  of  the  principles  of  a  science  is  the 
surest  test  of  their  understanding.  The  more  thor- 
oughly students  are  drilled  with  Problems,  the  surer 
is  the  teacher  that  his  work  has  been  worth  while. 
To  save  time,  and  such  is  recognized  as  a  distinct  factor 
in  modern  pedagogy,  problems  from  many  sources  have 
been  brought  together  in  this  book.  They  have  been 
taken  from  college  examinations  (American,  European, 
and  Australian),  regents'  examinations,  College  En- 
trance Examination  Board  papers,  text  books  of  all  kinds, 
and  such  books  dealing  especially  with  chemical  prob- 
lems, arithmetic,  or  calculations  as  those  of  Thorpe,  Tate, 
Foye,  Waddell,  Taylor,  Miller,  Hale,  Dennis,  Carpenter, 
Lupton,  Talbot,  etc.  Many  original  problems  have  also 
been  incorporated.  If  the  student  has  successfully 
solved  two  hundred  selected  problems  from  this  list, 
it  may  be  safely  said  that  he  has  acquired  a  fairly  sound 
comprehension  of  the  basic  principles  of  chemistry. 

No  attempt  is  made  to  incorporate  these  principles, 
for  they  are  gone  into  in  the  presentation  of  the  subject, 
whatever  text  may  be  used  or  whatever  method  be  pur- 
sued. A  type  series,  however,  is  given  in  Chapter  XIV. 
The  number  of  problems  is  sufficiently  great  to  admit 
of  the  use  of  the  book  a  number  of  years  before  solutions 
of  the  problems  may  be  handed  down  from  one  class 
to  another. 

42*17 


iv  PREFACE 

It  will  be  observed  that  the  student  must  seek  much 
necessary  information  from  his  text  or  such  handy 
reference  books  as  Biedermann's  Ohemiker  Kalendar 
or  Van  Nostrand's  Chemical  Annual  by  Olsen.  Our 
experience  has  shown  good  results  accruing  by  hav- 
ing such  reference  books  conveniently  placed  in  each 
laboratory. 

If  the  previous  training  of  the  student  has  been 
sound,  consideration  of  Chapter  I  may  be  omitted ;  but 
it  may  be  well  to  prove  this  by  testing.  It  is  a  remark- 
able fact  that  college  students,  although  they  may 
know  the  metric  system  thoroughly,  cannot  think  in 
its  terms  and  are  "  up  in  the  air"  as  soon  as  a  question 
is  propounded  in  meters,  cubic  centimeters,  etc. 

No  attempt  has  been  made  to  render  the  nomenclature 
uniform.  The  student  thus  has  an  opportunity  to  learn 
the  various  terms  in  good  usage  among  English-speak- 
ing peoples,  and  he  furthermore  becomes  more  or  less 
familiar  with  the  everyday  parlance  among  so-called 
practical  men. 

Our  thanks  are  due  Mrs.  W.  L.  Estabrooke  and 
Mr.  E.  A.  Stevens,  who  assisted  in  collating.  Mr.  W.  A. 
Hamor  kindly  followed  the  proofsheets. 

REVISED   EDITION 

Helpful  suggestions  on  the  part  of  many  teachers 
have  prompted  us  to  incorporate  much  useful  data  in 
an  appendix.  All  detected  errors  have  been  corrected 
and  a  booklet  containing  the  answers  to  the  problems 
has  been  prepared.  This  may  be  obtained  by  teachers 
on  request  to  the  publishers. 

CHARLES   BASKERVILLE. 

JUNE,  1911.  W.   L.   ESTABROOKE. 


CONTENTS 

CHAPTER  PAGE 

I.    MEASUREMENT 1 

Metric  System 

Linear  Measure  .         .         .         .         .         •         .  1 

Surface  Measure          ......  3 

Volume        ........  4 

Weight 6 

Thermometry 8 

Specific  Gravity  of  Solids  and  Liquids     .         .         .11 

II.     MOLECULAR  WEIGHTS  FROM  ATOMIC  WEIGHTS         .  16 

III.  PERCENTAGE  COMPOSITION 20 

IV.  CHANGES  IN  VOLUME 26 

i.     Due  to  change  in  pressure         ....  26 

ii.     Due  to  change  in  temperature  ....  29 

iii.     Due  to  change  in  both  pressure  and  temperature  34 
V.     VOLUMES    OF    GASES    FROM   WEIGHTS  —  SPECIFIC 

GRAVITY  AND  VAPOR  DENSITY  ....  48 

VI.     WEIGHTS  FROM  EQUATIONS 56 

VII.     VOLUMES  FROM  EQUATIONS       .        .        .        .        .80 
VIII.     PROBLEMS     IN    COMBINING    VOLUMES    OF    GASES 

(Gay-Lussac's  Law) 107 

IX.     CALCULATION  OF  FORMULAS      .....  118 
X.     ATOMIC  AND  MOLECULAR  WEIGHT  CALCULATIONS  129 
XI.     ELECTRO-CHEMICAL  PROBLEMS  .....  140 
XII.     ANALYTICAL  CALCULATIONS  —  STRENGTH  OF  SOLU- 
TIONS        143 

XIII.  REVIEW  —  SYSTEMATIC  AND  MISCELLANEOUS   .        .  164 

XIV.  PROBLEMS  BASED  ON  EQUATIONS      ....  225 


vi  CONTENTS 

APPBNDIX  PAGE 

I.     INTERNATIONAL  ATOMIC  WEIGHTS    ....  245 

II.    PERIODIC  ARRANGEMENT  OF  THE  ELEMENTS  .        .  246 

III.  THE  METRIC  SYSTEM  —  CONVERSION  TABLES  AND 

MENSURATION  RULES 247 

IV.  SPECIFIC  GRAVITIES  OF  GASES          ....  251 
V.    PHYSICAL  CONSTANTS  OF  THE  ELEMENTS         .        .  252 

VI.    VOLUME  AND  WEIGHT  OF  WATER  FROM  0°  TO 

31°  C 258 

VII.    VAPOR  PRESSURE  OF  WATER  FROM  0°  TO 

+  100°C 259 

VIII.    ELECTRO-CHEMICAL  EQUIVALENTS     .        .        .        .  260 

IX.     UNITS  OF  ELECTRICITY,  HEAT,  AND  POWER    .        .  261 

X.     HEATS  OF  COMBINATION 262 

XI.     SPECIFIC  RESISTANCE  OF  VARIOUS  SUBSTANCES      .  263 

XII.  DENSITIES  OF  VARIOUS  SUBSTANCES         .        .        .  264 

XIII.  TABLE  OF  SOLUBILITIES 266 

XIV.  PREPARATION  OF  SOLUTIONS 271 

XV.    STANDARD  STOCK  SOLUTIONS 275 

XVI.     COMPARISON  OF  CALCULATED  AND  OBSERVED  DECOM- 
POSITION ;  VOLTAGES  OF  AQUEOUS  SOLUTIONS     .  278 


PROGRESSIVE   PROBLEMS   IN 
CHEMISTRY 

CHAPTER   I 

Introduction 

MEASUREMENT 

Metric  System  —  Linear  Measure 

1.  Express    263.7018    m.    as    <»    dm.  ;     (b)    cm.  ; 
(<?)  mm.  ;    (d)  Dm.  ;    0)  Hm.  ;    (/)  Km. 

2.  Express  as  m.  (a)  5  Dm. ;  (6)  4  Hm.  ;  (<?)  9  Dm. ; 
00  8  Km.;   (e)  32  Hm.;   (/)  360  cm.;   (#)  630  mm. 

3.  How  many  mm.   in  (a)  13  Km. ;    (5)  92  Hm. ; 
(<0    BOO    Dm.;     (d)    26.91    m.  ;     (e)    86.312    dm.; 
(/)  8  cm.? 

4.  In   a   mile   how   many    Km.  ?      How   many  m.  ? 
How  many  cm.  ? 

5.  Express  10  yd.  in  m.  ;  in  Km. ;  in  Hm.  ;  in  cm. ; 
in  mm. 

6.  In   31.76  ft.  how  many  m.?     How  many  Km.? 
How  many  cm.  ?     How  many  dm.  ? 

7.  Convert  83  in.  into  (a)  mm.;   (&)  cm.;  (<?)  Km.; 
(<T)  Hm, ;   (»  dm. 

8.  Find  the  value  of  the  following  expressions  in  m.  : 
O)  0.435  m.  +  852  cm.-f  4263  mm.  +  0.159  Km. ; 
(b)  0.927  Km.  -  6495  cm.,  4.37  cm.  -  42.87  mm. ; 

l 


2         PROGRESSIVE   PROBLEMS   IN   CHEMISTRY 

(<?)  8  x  0.0457  Km.,  3.04  x  60.93  cm.,  5.43  x  67.2  mm.; 
(<f)  38,019  mm.  -i-  0.097,  0.14  Km.  -*-  25.625. 

9.  A  book  is  2.1  cm.  thick;  if  the  average  thick- 
ness of  the  leaves  is  0.05  mm.,  find  the  number  of 
pages  in  the  book. 

10.  The  cost  of  building  a  railroad  is  $ 25,000  per 
Km.;  what  is   the   cost  of  the   road,   if  its  length  is 
72  Km.  and  53  in.? 

11.  The  wheels  of  a  locomotive  that  make  45  Km. 
an  hour  are  7.5  m.  in  circumference ;  how  many  revo- 
lutions will  they  make  a  minute? 

12.  A  train  goes  1248  m.  in  1J  min. ;  how  many  Km. 
will  it  go  in  1  hr.,  35  min.,  and  15  sec.? 

13.  The  top  of  a  monument  is  143.9  m.,  and  the  base 
67.19  m.  above  the  level  of  the  sea;  the  steps  which 
lead   from  the  base  to  the  top   of  the  monument  are 
each  19  cm.  high.     How  many  steps  are  there? 

14.  Sound  travels  1130  ft.  per  second;    how  many 
meters  does  it  pass  through  per  second? 

15.  It  is  92,000,000  miles  to  the  sun ;  how  many  Km. 
is  it? 

16.  Light  travels  186,000  miles  per  second ;  how  many 
Km.  per  second  is  that  ? 

17.  The  mean  height  of  the  barometer  in  the  latitude 
of  Greenwich  at  the  level  of  the- sea  is  30  in.;  to  how 
many  mm.  is  this  equivalent? 

18.  How  many  dm.  are  equivalent  to  106,725  mm.? 

19.  How  many  miles  are  there  in  15  Km.? 

20.  In  an  English  inch  are  contained  25.3995  mm.; 
how  many  Km.  are  there  in  a  mile? 


MEASUREMENT  3 

21.  A  nautical  fathom  is  6.087  ft. ;  what  is  its  value 
in  m.  ? 

Surface  Measure 

22.  Multiply  5  dm.  by  3  mm.,  and  give  the  answer  in 
cm. 

23.  Reduce  and  give  the  answers  to  the  following  in 
cm.2:    (a)  1.51   m.  x  2.5   dm.;  (6)   0.35  m.  x  3   cm.; 
(c)  10  dm.2 -r-4  cm.;  (d)  1.3  m.2 -T- 3  cm. 

24.  Measure  the  length  and  breadth  of  a  sheet  of  paper 
and  give  the  result  in  decimeters;  then  compute  how 
many  cm.2  could  be  cut  from  it. 

25.  Calculate  the  number  of  cm.2  contained  on  the 
surface  of  a  filter  paper  having  a  radius  of  5  cm. 

26.  A  round  filter  paper  is  10  cm.  across;  what  is  its 
area? 

27.  How  many   cm.2  are  there  in  15.5m.2?     How 
many  dm.2  are  contained  in  108,642  cm.2  ? 

28.  Required  the  number  of  mm.2,  cm.2,  dm.2,  con- 
tained in  the  top  of  a  table  measuring  1m.  x  70  cm. 

29.  Reduce  the  following  to  cm.2:   (a)    2.8    dm.2; 
(5)  3.1dm.2;  (c)  1.35m.2;  (d)  0.75dm.2  ;  0)  0.032  m.2; 
(/)  0.0064dm.2;  (<?)  700m.2. 

30.  Reduce   the    following   to  dm.2:   (a)   53    cm.2; 
(£)  7.3cm.2;  (c)  0.003  cm.2;  (d)  25m.2;  <»  0.33  cm.2; 
(/)  28.03  m.2. 

31.  How  many  cm.2  in  a  square  one  side  of  which  is 
(a)  1.7  dm.;   (6)  35  dm.;   (V)   1  m. ;    (d)   0.035  dm.; 
0)  3.2  dm.? 

32.  How    many    cm.2   in    the   following  rectangles: 
(a)    2dm.  x  6cm.  ;    (6)    0.07m.  x  7 cm.;    (c)    3.2dm. 
X  0.2  dm. ;  '(<f)  58  dm.  x  25  cm.  ? 


4        PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

33.  Express  1  mm.2  as    (&)  the  decimal  of  a  cm.2; 
(6)  of  a  m.2;   (c)  of  a  dm.2. 

34.  Compute  the  area  of  a  filter  paper  12  cm.  in  dia- 
meter.   7T  =  3.14. 

35.  Required  the  number  of  (a)  cm.2,  (5)  dm.2,  and 
(c)  m.2  in  1,098,765,421  mm.2. 

36.  How  many  m.2  in  9  Dm.2;   8  Hm.2;  13  Km.2? 

37.  How  many  ca.  in  9  a. ;  in  a  Ha.  ? 

38.  What  part  of  a  Ha.  is  an  a.;  a  ca.  ? 

39.  What  part  of  a  m.2  is  a  dm.2;  a  mm.2? 

40.  Convert  1,854,276  m.2  into  Ha.;  into  Km.2. 

41.  Write  1.7431  m.2  as  cm.2;  as  mm.2. 

42.  How  many  Km.2  in  17,467.5  Ha.? 

43.  How  many  cm.2  in  0.0137  m.2? 

44.  Write  3.571  cm.2  as  mm.2. 

45.  A  man  bought  3  Ha.  of  land  at  |2.00  per  Ha. 
and  sold  it  for  $  2.50  per  a.  ;   how  much  did  he  gain  ? 

Volume 

46.  A  cellar  20  m.  x  50  m.  x  3  m.  is  to  be  excavated; 
what  will  it  cost  at  12  cents  per  m.3? 

47.  How  many  cc.  are  there  in  a  block  12  cm.  long, 
8  cm.  wide,  and  5  cm.  high? 

48.  How  many  m.3  are  there  in  a  wall  25  m.  long, 
8.4  m.  high,  and  76  cm.  wide? 

49.  A  wood  pile  contains  1800m.3;  it  is  15m.  long 
and  12  m.  wide.     How  high  is  it? 

50.  How  many  cm.2  are  there  in  one  face  of  a  cube 
containing  729  cc.  ? 


MEASUREMENT  5 

51.  A   gallon  is  equal  to  3.7851.;  how  many  cc.  are 
contained  in  one  pint  ? 

52.  Reduce  16  1.  to  U.  S.  gallons. 

53.  A  beaker  6  cm.  in  diameter  and  8  cm.  high  will 
hold  how  many  1.  of  water? 

54.  A  pneumatic  trough  is  3.1  dm.  long  by  1.9  dm. 
wide  and  1.5  dm.  high,      (a)  How  many  1.  of  water 
will  it  hold?     (6)  How  many  dl.  of  water?      (Y)  How- 
many  cl.  ?     (cT)  How  many  ml.  ? 

55.  A  cistern  1.42  m.  x  8.4  dm.  x  53  cm.  will  hold 
what  weight  and  volume  of  water? 

56.  A  box  is  1.2  dm.  x  7  cm.  x  30  mm.     What  is 
the  capacity  in  cc. ;    also  in  1.  ? 

57.  Compute  the  contents  of  these  boxes  in  1.  and  in 
cc. :   (a)  12  cm.  x  5  cm.  x  4  cm. ;  (5)  2.1  dm.  x  3.2  dm. 
X  10  cm.;    <V)  1.04  m.  x  1.03  m.  x  1.02  m. 

58.  How  many  cc.  in  a  slab  of  marble  1.5  m.  x  7  dm. 
x  9  cm.  ?     How  many  1.  of  water  will  such  a  slab  dis- 
place ? 

59.  Reduce  the  following  to  cc. :    (a)  3.7  dm.3;  (5) 
5.02  dm. »;  (<?)  1.001  dm. 3;    (d)  0.003  dm. 3;    (V)  200 
mm. 3 . 

60.  Reduce  and  express  the  following  as  indicated  : 
(a) 2  dm.3  to  mm.3;  (5)   5.7  dm.3  to  mm.3;   (V)  33.33 
cm.3  to  m.3;  (d)  1.07  dm.3  to  m.3. 

61.  A  stick  of  timber  4  m.  long  and  3  dm.  wide  has 
a  solid  contents  of  240  dm.3;  what  is  its  thickness? 

62.  What  is  the  capacity  in  1.  of  a  rectangular  tank 
2  m.  long,  9  dm.  wide,  and  8  dm.  deep? 

63.  What  is  the  volume  of  a  spherical  glass  bulb 
which  has  a  radius  of  3  cm.? 


6        PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

64.  How   many  1.    of  air  are  contained  in  a  room 
measuring  4  m.  x  3  m.  x  2  m.? 

65.  In  1.5  pints  there  are  how  many  cc.?   How  many 
mm.3  ? 

66.  How  many  1.  of  water  are  contained  in  a  tank 
3  m.  x  1.6  m.  x  1.4  m.? 

67.  How  many  HI.  in  a  bin  4  m.  x  2  m.  x  1  m.  ? 

68.  How  high  must  a  box  be  to  hold  30  1.  if  it  is  50 
cm.  long  and  20  cm.  wide  ? 

69.  In  a  m.3,  how  many  dm.3  ;  cc.3?     What  part 
of  a  m.3  is  a  dm.3;  a  cc.3? 

70.  How  many  m. 3  in  a  rectangular  box  125  cm.  x 
112  cm.  x  80  cm.  ?     How  many  1.  ? 

71.  How  deep  must  a  cistern  be  to  hold  6000  1.  if  the 
bottom  is  a  square  measuring  2.25  m.  on  a  side? 

72.  How  many  m. 3  of  earth  must  be  removed  to  dig 
a  ditch  90  m.  x  85  cm.  x  50  cm.  ? 

73.  A  cistern  is  2m.  x  1.5  m.  x  1  m.  ;  how  many  1. 
of  water  will  it  hold  ? 

74.  A  cylinder  of  a  steam  engine  is  3  ft.  in  diameter 
and  5  ft.  long;  how  many  dm. 3  of  steam  will  it  contain  ? 

Weight 

75.  How  many  g.  in  1  Kg.;    8  Dg. ;    and  6   Hg.  ? 
What  part  of  1  g.  is  1  eg. ;  1  dg. ;  1  mg.? 

76.  In  a  ton  how  many  Kg.  ?     How  many  g.  ? 

77.  A  HI.  of  water  weighs  how  many  Kg.  ?    What 
part  of  a  ton  ? 

78.  Change  0.546  Kg.  to  g.;  to  mg.;  to  eg. 

79.  Change  0.391  of  a  ton  to  Kg. 


MEASUREMENT  7 

80.  How  many  eg.  are  contained  in  2. 567  Kg.  ?     How 
many  g.  are  contained  in  1.725  Kg.  ? 

81.  How  many  eg.  are  contained  in  2.567  Kg.?     How 
many  mg.  are  contained  in  5  cc.  of  water  at  -f-4°C.? 

82.  How    many  mg.    are    there    in    0.9  dg.  ?     How 
many  in  1  Kg.  ? 

83.  A  cylindrical  tube  90  mm.  in  length  holds  1  g.  of 
water  at  +  4°  C.     Calculate  its  internal  diameter. 

84.  What  is  the  weight  of  water  in  a  tank  1.3m. 
x  80  cm.  x  250  mm.? 

85.  How  many  g.   of  water  in  a  bottle  containing 
0.391  1.? 

86.  A  sample  of  water  contains  4  g.  of  solid  matter 
per  1. ;  to  how  many  g.  per  gallon  does  this  correspond? 

87.  A    tank    measures   2.5  m.  x  3  m.  x  6  m. ;  how 
many  1.  of  water  will  it  hold?     How  many  Kg.  ? 

88.  A  ton  equals  1016.05  Kg.  ;  how  many  g.  in  1  Ib. 
avoirdupois? 

89.  A  piece  of  platinum  foil  measuring  10.5  cm.  by 
1.5  cm.   weighs  0.723  g.;  into  how  many  pieces,  each 
weighing  1  dg.,  may  it  be  divided  ? 

90.  A  fine  wire  255  mm.  in  length  weighs  0.172  g.; 
what  length  of  such  wire  would  it  take  to  make  a  eg. 
«  rider  "  ? 

91.  How  much  space  will  3.750  g.  of  water  occupy? 

92.  A  piece  of   Swedish  filter  paper  measuring   60 
cm.2  leaves  on  burning  0.1062  g.   of  ash.      Calculate 
the  amount  of  ash  left  on  burning  filters  possessing  the 
following  radii:   (a)   3   cm.;   (5)  4    cm.;    (<?)    5    cm.; 
00  6  cm. ;   0)  8  cm. ;   (/)  10  cm. 


8         PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

93.  Required  the  number  of  mg.  in  115  cc.  of  water 
measured  at  +  4°  C. 

94.  A  silver  coin  weighs  30  g. ;   what  volume  of 
water  will  it  balance  ? 

95.  A  piece  of  platinum  foil  is  5.2  cm.  x  0.7  cm.  and 
weighs    0.8  g. ;    into  how  many  pieces,  each  weighing 
1J  dg.,  may  it  be  cut? 

96.  What  weight  of  water  is  required  to  fill  a  vat 
98  cm.  x  71  cm.  x  38  cm.? 

97.  A  mass  of  21.7  g.  is  divided  into  70  pills;  what 
is  the  weight  of  each  pill? 

98.  At  2  cents  a  Kg.,  what  will  2.25  tons  of  hay  cost? 

99.  At  $  6  a  ton  for  coal,  what  will  it  cost  to  heat 
a  building  30  days  if  it  takes  400  Kg.  of  coal  a  day  ? 

100.  Into  how  many  pieces  of  325  mg.  each  may  a 
mass  of  23.4  g.  be  divided  ? 

101.  A   liter   of    mercury    weighs   13    Kg.    598    g.; 
find  the  weight  in  Kg.  of  3.69  1. 

102.  If  16.94  1.  of  olive  oil  weigh  15  Kg.  500  g.,  find 
the  weight  of  1  1. 

Thermometry 

103.  What  temperature  on  the  C.  scale  is  equivalent 
to  +  250°F.? 

104.  What  temperature  C.  corresponds  to  —  250°  F.? 

105.  Change  0°  F.  to  0°  C. 

106.  Express  +  40°  C.  on  the  Fahrenheit  scale. 

107.  Convert  the  following  temperatures  to  C.°: 
+  40°  F.,  +  2100°  F.,  -  70°  F., 
-  40°  F.,                -  28°  F.,            +  2700°  F. 


MEASUREMENT  9 

108.  Express  the  following  temperatures  in  F.°  : 

+  125°  C.,  +  60°  C.,  +  312°  C., 

+  15°  C.,  +  480°  C.,  -  273°  C. 

109.  A  Fahrenheit  thermometer,  immersed  in  a  cer- 
tain   hot    fluid,    rises    through     -f-  50° ;     through    how 
many  degrees  would  a  Centigrade  thermometer  have 
risen  under  the  same  circumstances  ? 

no.    What  is  the  difference  in  temperature  between 
+  72°  C.  and  +  72°  F.  ? 

111.  What  temperature  on  the  Centigrade  scale  is 
equal  to  +  212  F.  ? 

112.  Express  the  following  temperatures  in  C.° : 
+  60°F.,  -15.5°F.,  +0.2°F. 
+  10°  F.,              +  500°  F., 

113.  Express  the  following  temperatures  in  F.° : 

+  4°  C.,  +  60°  C.,  +  212°  C., 

+  15.5°C.,  +0.1°C.,  +1°C. 

114.  Reduce  the  following  Centigrade  degrees  to  the 
Absolute  scale  : 

+  37°C.,  +26°C.,  +273°C.,  +11°C.,  - 12°  C., 
+  55°  C.,  + 18°  C.,  +  40°  C.,  -  40°  C. 

115.  Reduce  the  following  Fahrenheit  degrees  to  the 
Absolute  scale : 

+  25°  F.,  +  60°  F.,  +  1°  F.,  -  8°  F.,  -  30°  F. 

116.  Reduce  the  following  Fahrenheit  temperatures 
to  the  Centigrade  scale  : 

+  68°  F.,  +  36°  F.,  +  30°  F.,  +  32°  F.,  0°  F.,  -  40°  F., 
-  44°  F.s  -  36°  F.,  +  10°  F.,  -  10°  F.,  -  1°  F. 


10       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

117.  Reduce    the    following    Centigrade    degrees   to 
Fahrenheit : 

+  72°  C.,  +  36°  C.,  0°  C.,  +  4°  C.,  -4°  C.,  -  40°  C., 
+  40°  C.,  -  273°  C.,  +  273°  C.,  -  1°  C.,  +  1°  C. 

118.  What  must  be  the  temperature  of  a  liquid  so 
that  both  the  Fahrenheit  and  Centigrade  thermometers 
shall  read  the  same  when  immersed  in  it  ? 

119.  Reduce  +  8°  C.,  +  20°C.,  +  70°  C.,   -  40°  C., 
and  +10°  C.  to  the  Fahrenheit  scale. 

120.  Reduce  +  8°  F.,  +40°  F.,  +  180°  F.,  -  10°  F., 
and  +  36°  F.  to  the  Centigrade  scale. 

121.  Change  these  to  the  Absolute  scale  : 

+  79°  F.,  +  79°  C.,  +  31°  C.,  -  60°  C.,  -  5°  C. 

122.  Sulphuric  acid  boils  at  -f-  338°  C. ;  what  is  the 
corresponding  boiling  point  on  Fahrenheit's  scale  ? 

123.  Cast   iron    melts    at    +  2822°    F.    and    tin    at 
+  455°  F. ;  what  is  the  difference  between  their  melt- 
ing points  expressed  in  Centigrade  degrees  ? 

124.  Bromine  boils  at  +138.7°F. ;  what  is  the  cor- 
responding temperature  on  the  Centigrade  scale  ? 

125.  Absolute  zero  is  273°  below  zero  on  the  Cen- 
tigrade scale;  what  is  this  temperature  on  the  Fahren- 
heit scale? 

126.  Iron  melts  at  + 1200°  C. ;  what  is  the  melting 
point  on  the  Fahrenheit  scale? 

127.  The  average  difference  in  temperature  between 
two  places  is  +  60°  F.  ;  how  much  would  this  be  on  the 
Centigrade  scale  ? 

128.  A  low  artificial  temperature  obtained  is  — 140°  C . ; 
what  is  the  corresponding  temperature  in  F.  degrees  ? 


MEASUREMENT  11 

129.  Chloroform  boils  at  +61.2°  C.,  turpentine  boils 
at  4-  156°C.,  and  glycerine  boils  at+290°C.;  what  are 
the  Fahrenheit  readings? 

130.  At  a  certain  temperature  C.  scale  the  reading  is 
as  much  below  0°.C.   as  it  is  above  on  the  F.   scale. 
Find  the  readings. 

131.  Ether  boils  at  +  34.5° C.,  alcohol  at  +  78.4° C., 
and  sulphuric  acid  at  +  338°C.  ;  what  are   the   corre- 
sponding boiling  points  on  Fahrenheit's  scale  ? 

132.  Mercury  freezes  at  -  40°  C.  and  boils  at  +  350°  C. 
Calculate  the  corresponding  temperatures  on  the  scales 
of  Reaumur  and  Fahrenheit. 

133.  Cast  iron  melts  at  +1075°  C.,  zinc  at  +423°  C., 
lead  at  +  334°  C.,  tin  at  +235°  C.     Calculate  these  tem- 
peratures in  F.  degrees. 

134.  The  difference  between  readings  on  C.  and  F. 
scale  is  64.     Find  the  reading. 

Specific  G-ravity  of  Solids  and  Liquids 

135.  A  piece  of  metal  weighs  24.076  g.  in  air  and 
21. 2436  g.  in  water;  what  is  its  sp.  gr.  ? 

136.  A  piece  of  mineral  weighs  47  g.  in  air  and  36.555 
g.  in  water;  what  is  its  sp.  gr.  ? 

137.  A  piece  of  iron  ore  weighs  27  g.  in  air  and  21.6  g. 
in  water ;  what  is  its  sp.  gr.  ? 

138.  A  certain  fine  powder  weighs  in  the  air  7  g. ;  when 
this  powder  is  placed  in  a  flask,  and  this  flask  is  then 
filled  with  water  to  a  mark  on  the  flask,  the  weight  of 
the  flask,  powder,  and  water  to  the  mark  is  59  g.     The 
weight  of  the  flask  filled  with  water  only  to  the  mark 
is  55 g.     What  is  the  sp.  gr.  of  the  insoluble  powder? 


12       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

139.  A  certain  fine  sand  weighs  12  g.  in  the  air.     A 
flask  filled  with   water  to  mark   weighs  47. 6  g.     The 
same  flask  containing  the  sand  and  filled  to  the  same 
mark  with  water  weighs  56. 5  g.     What  is  the  sp.  gr.  of 
the  sand? 

140.  An  empty  bottle  weighing  3. 5305  g.  weighs  when 
filled  with  pure  water  7. 6722  g.,  when  filled  with  sea- 
water  7. 7849 g.     What  is  the  sp.  gr.  of  sea  water? 

141.  A  sample  of  sugar  weighs  7.5  g.  in  the  air  and 
4.6g.  in  petroleum  ether  of  sp.  gr.  0.64;    what  is  the 
sp.  gr.  of  the  sugar  ? 

142.  Find  the  sp.  gr.  of  common  salt  from  the  follow- 
ing data  :  weight  of  salt  in  air,  8.85  g. ;  weight  of  flask 
and  turpentine  to  mark,  45.24  g. ;  weight  of  flask,  salt, 
and  turpentine  to  mark,  50.56  g.;  sp.  gr.  of  turpentine, 
0.86  g. 

143.  Find  the  relative  densities  of  the  following  sub- 
stances: 

Granite  Marble  Hematite 

Weight  in  air       409.82  g.      53.2841  g.          13.6287  g. 
4*  water  259. 31  g.      33.4020  g.          10.9406  g. 

144.  A  sp.   gr.   flask  holds  2.545    mg.    of    alcohol, 
42.740  of  mercury,  and  5.829  of  sulphuric  acid.    Calcu- 
late the  relative    density    of    the  sulphuric   acid   and 
mercury,  the  density  of  the  alcohol  being  0.80. 

145.  A  solid  weighs  in  a  vacuum  100  g. ;  in  water 
85  g.;  and  in  another  liquid  88  g.     What  is  the  relative 
density  of  this  liquid? 

146.  Determine   the   relative    density  of  gold  from 
the  following  data  : 

Weight  of  gold  in  air  4.6764  g. 

Loss  of  weight  in  water      0.2447  g. 


MEASUREMENT  13 

147.  A  glass  rod   weighing  13  g.  in  air  weighs  8  g. 
in  water  and  3.8  g.  in  sulphuric  acid;  what  is  the  sp.  gr. 
of  the  sulphuric  acid  ? 

148.  A  piece  of  iron  sulphide  weighed  in  air  4.8934  g.  ; 
in  water  it  weighed  3.8860  g.     Calculate  its   relative 
density. 

149.  Find  the  weight  of  a  block  of  sulphur  50  m.3  in 
Yolume  and  of  relative  density  2.05. 

150.  What  is  the  weight  of  1  1.  of  bromine,  sp.  gr. 
3.19;  of  burning  oil,   sp.   gr.   0.83;    of  alcohol,  sp.  gr. 
0.80;  of  mercury,  sp.  gr.  13.59? 

151.  What  is  the  volume  of  1   Kg.  of  iron,  sp.  gr. 
7.85;  of  magnesium,  sp.  gr.  1.74;   of  platinum,  sp.  gr. 
21.5;  of  ice,  sp.  gr.  0.92? 

152.  A  bottle  holds  336  g.  of  water;   it  also  holds 
577.9  g.  of  sulphuric  acid.     What  is  the  sp.  gr.  of  the 
acid? 

153.  A  bottle   weighs   80  g.  when   empty.     Filled 
with   water  it  weighs  230  g.     Filled  with  bromine  it 
weighs  560  g. ;  with  hydrochloric  acid,  260  g.     What  is 
the  sp.  gr.  of  the  bromine  and  of  the  acid  ?     What  is 
the  capacity  of  the  bottle? 

154.  A  bar  of  gold  measures  34  by  10.5  by  11  cm., 

and  weighs  75.87  Kg.;  what  is  the  sp.  gr.  of  the  gold? 

155.  A  block  of  wood  measures  49.8  by  60.5  by  210. 
cm.;   its  sp.  gr.    is  0.63.     What  is  the   weight  of  the 
block? 

156.  What  is  the  weight  of  a  m.3  of  bromine,  sp.  gr. 
3.19;  of  water  at  +4°  C.;  of  sulphuric  acid,  sp.  gr.  1.84? 

157.  The  sp.  gr.  of  HNO3  is  1.52.     (a)  Find  weight 
of  20  cc. ;   (5)  87  cc.  ;   (V)  how  many  cc.  in  100  g.  ? 


14       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

158.  What  is  the   weight  of  40  cc.  of  sulphuric  acid 
having  a  sp.  gr.  of  1.84? 

159.  What  is  the  volume  of  3.6  Kg.  of  alcohol  having 
asp.gr.  of  0.80? 

160.  A  piece  of  metal  weighs  3.7395  g.  in  air,  1.578  g. 
in   water,   and  2.2896   g.   in   another  liquid;    what  is 
the  sp.  gr.  of  the  metal  and  of  the  liquid? 

161.  A  piece  of  platinum  foil  14.2  cm.  long  and  2.5 
mm.  broad  weighs  12  g.;  find  the  thickness.     Density 
of  platinum  =  21.5. 

162.  A  body  weighing  18.5  g.  when    under    water 
weighs  16.4  g.  and  when  in  naphtha  16.72  g. ;  what  is 
the  sp.gr.  of  the  naphtha? 

163.  Find  the  mass  of  1  m.3  iron.    Sp.  gr.  Fe  =  7.80. 

164.  A  mercury  barometer  stands  at  76.1  mm.;  what 
would    be     the    reading   on   a   glycerine    barometer? 
Sp.  gr.  glycerine  is  1.26,  mercury  is  13.59. 

165.  Nitric  acid  being  1.52  times  as  heavy  as  water, 
what  is  the  weight  of  1  1.  of  the  acid  ? 

166.  A  piece  of  sodium  weighed  14.1563  g.  in  dry 
air  and  2.1807  g.  in  kerosene  of  sp.gr.  0.83;  what  is 
the  sp.  gr.  of  sodium  ? 

167.  A  piece  of  metal  weighs  47  g.   in  water  and 
48.756  g.  in  petroleum  ether  of  sp.  gr.  0.66;  what  is 
the  sp.  gr.  of  the  metal  ? 

168.  A  piece  of  brass  weighs  10  g.  in  air,  8.824  g.  in 
water,  and  9  g.  in  turpentine.     Calculate  the  sp.  gr.  of 
the  turpentine. 

169.  If  sulphuric  acid  has  a  sp.  gr.  of  1.84,  how  many 
cc.  of  it  will  weigh  80  g.  ? 


MEASUREMENT  15 

170.  A  block  of  marble  5cm.  x  4cm.  x  3cm.  has  a 
sp.  gr.  of  2.7;  how  many  g.  will  it  weigh? 

171.  A  lump  of  sodium  carbonate   (sp.   gr.  =  1.45) 
is  65mm.  x  .4dm.  x  3cm.;  what  does  it  weigh? 

172.  The  sp.  gr.  of  sulphuric  acid  is  1.84.     A  carboy 
holds  5  gal.  of  231  in.3  each.     How  heavy  would  the 
contents  of  this  carboy  be? 

173.  What  is  the  densit}^  of  a  cube  of  oak  9  mm. 
along  each  edge  and  which  weighs  0.62g.? 

174.  A    cylinder   of    mahogany    10.1cm.    high   and 
9.4  cm.  across  weighs  405.7  g.     Find  its  density. 

175.  A  block  of  steel  (sp.  gr.  =  7.6)  is  10  cm.  square 
and  1.8315  cm.  thick.     Find  the  mass  of  it  in  g. 

176.  What  is  the  mass  of  a  m.3  of  hematite  (sp.  gr. 
=  5.25)? 

177.  Find  the  volume  of  1000  g.  of  sea  water  (sp.  gr. 
=  1.03). 

178.  Find  the  mass  of  a  m.3  of   anthracite  (sp.  gr. 
=  1.4). 

179.  How  many  tons  does  a  block  of  granite  (sp.  gr. 
=  2.7)  10  x  3  x  2m.  weigh? 

180.  If  a  glass  ball  weighing  7.7158  g.  2  cm.  in  diam- 
eter  just   floats   in   a  liquid,  find   the   sp.  gr.  of   the 
liquid. 

181.  What  is  the  density  of  K2Cr2O7,  if  6. 2138  g.  of 
it  displace  2.0532  g.  of  benzene  (sp.  gr.  =  0.88)? 


CHAPTER   II 

Molecular  Weights  from  Atomic  Weights 
MOLECULAR  WEIGHTS 

Calculate  the  molecular  weights  of  the  following: 

1.  HC2H302;      AlBr3;      A14C3  ;      A12O3;      A1I3 ; 
A1(N03)3;  A1P04;  A12(SO4)3;  K2A12(SO4)4,24  H2O. 

2.  NH4C1;  (NH4)2C03;  NH4HCO3;  (NH4)2CrO4; 
NH4CN;    NH4F;   (NH4)2MoO4 ;    NH4NO3;  NH4NO2. 

3.  NH4C1O4;    NH4H2P04;    (NH4)2S ;     NH4CNS; 
(NH4)2W4013,8H20. 

4.  SbBr3;        SbH3;       Sb2O3;        SbOCl;       Sb2S3; 
H3AsO4;    As2O3. 

5.  AuCl3;       Au2O3;      Au2S3;      AuBr3;       Au2O ; 
Ba(C2H302)2,  H20 ;  BaCO3. 

6.  BaCrO4;      BaF2 ;      BaSO4;     BiBrg;     BiONO3; 
Bi2S3;  H3B03;  B6C. 

7.  BrCl,10H20;  CdSO4;   CdO ;  CdS ;  Cd(NO3)2; 
Cd(CN)2;  CdWO4;  CsCl;  CsBr;  Cs2S5. 

8.  CaCO3;         CaAl2O4;          Ca(HCO3)2;        CaO; 
Ca(ClO3)2;  CaF2;  Ca(OH)2;  CaI2;  CaSO^;  CO2. 

9.  C2Br4;  C2C14;  CS2 ;  CO. 

10.    CeC2;  Ce(NO3)4;    CeO2;   CeCl3;  C12O;  C12O7; 
Cr03;  CrCl3;  Cr2(SO4)3. 

16 


MOLECULAR  WEIGHTS  17 

11.  CrO2Cl2;        Co2P;         CoCl2;        Co(NH3)6Cl3; 
Co(OH)3;       CbBr5;       CbH ;       CbN;      Cb(HC2O4)5; 
CbOBr3;    Cb2OS3. 

12.  CuBr2;  Cu2O;  CuSO4,5H2O;  CuCO3;   CNOH; 
C2N2;  ErCl3,6H20;  Er2O3;  Er2(SO4)3. 

13.  FeAsO4,2H2O;  FeCla  ;  FeCl3;  FeCO3;  Fe3O4; 

FeS. 

14.  Ga2(SO4)3;    Ga2S3 ;    GeBr4 ;    GeOCl2;    BeCO3; 
BeF2. 

15.  Au2P3  ;  NH2,NH2  ;  HC1 ;  HCN  ;  H2O2  ;  NH2OH ; 
InBr3;   InCl3. 

16.  In(CN)3;     HIO3;     Id;     IrI3 ;     IrS2 ;     Fe3C  •, 
LaC2;   La2O3;  La2(SO4)3;   La2S3. 

17.  Pb(C2H302)2;          Pb(B02)2,H20;          PbBr2; 
Pb(N03)2;   PbO;    Pb3O4. 

18.  PbO2;   LiBr;   LiOH ;    LiNO3;   Li2C2O4;   Li2O ; 
MgC03. 

19.  MgF2;      MgSO4,7H2O;    MnCl2 ;      Mn(OH)2  ; 
HgCl2;  HgS04. 

20.  HgCl;     HgS;     MoC ;    MoCl3 ;    MoSa;     NdCl3, 
6  H20 ;  NdC2. 

21.  NiAs;     Ni(C2H3O2)2;     NiCO3;     HNO3;     N2; 
N20;  NOC1. 

22.  OsCl2;    OsO4;    OsS2;    O2 ;    PdBr2 ;    Pd(CN)2 ; 
PdS04,  2  H20. 

23.  PF3;   PBr2N;   Pt2O3  ;   PtBr2;     K2A12O4,  3  H2O; 
K2PtCl4;   KOH;   PrCl3. 

24.  Pr2S3;      RaBr2;      RaC]2 ;      RhCl3 ;    Rh(SH)3; 
Rh(OH)3;  RbBr;  Rb2CO3 ;  RbF ;  RbOH. 


18       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

25.  RuCl2  ;  Ru(OH)3;    Ru2O3;   SmC2 ;   Sm(NO3)3, 
6  H20 ;  Sc203. 

26.  Sc2(SO4)3;    Se2Br2;    SeCl2 ;    SeOCl2  ;   SiHBr3 ; 
SiF4. 

27.  AgC2H302;    AgBr03;    AgCl;    Ag2Se ;    Ag2S ; 
NaCl;  Na2SO4. 

28.  NaNO3;   NaHCO3;    NaAuCl4,  2  H2O  ;    Na8VO4, 
16H2O;  Na2WO4,  2  H2O. 

29.  SnO2;      Sn2Fe(CN)6;     SnFa ;     SrBr2;       SrC2 ; 
Sr(Br03)2,H20;   H2SO4  ;   SOBr2  ;  TaBr5. 

30.  Ta205;   H2C4H406;  TeO2 ;  Tb2O3. 

31.  T1F;    T10H;    T1(NO3)3;    ThBr4  ;    Th(C2O4)2 ; 
Ti6(CN)4;  Ti203. 

32.  WBr2;W2C;  WC14;   WO2;   H2WO4;  H2UO4; 
U2C3. 

33.  U02C12;    HV03;    VF3,  3  H2O  ;    Yb(C2H3O2)3, 
2H02;      Yb203;       Yb2(SO4)3;      YtBr3 ;      Yt(NO8)8, 
4H20. 

34.  ZnF2;       Zn2Fe(CN)6,  3  H2O  ;       ZnSO4,6H2O; 
ZrBr4;    Zr(OH)4;    ZrOCla,  8  H2O  ;    Zr(SO4)2,  4  H2O. 

35.  What  are  the  molecular  weights  of  the  minerals 
having  the  following  formulas:  (Ag2Pb)Se;  (AgCu)2S  ; 
CuaSe  ;       (PbHg2)Se  ;       (PbCuAg2)Se  ;      Hg(SSe)  ; 
(HgZn)S;  NiSb. 

36.  Ni(SbAs);       Fe16S16;      CoS2,CoAs;       PtAs2 ; 
RuS2;       FeS2,FeAs;      NiS2,Ni(AsSb)2;      Cu2S,Bi2S3 ; 
MnS2. 

37.  9Ag2S,Sb2S3;      Ag(ClBrl);      (FeMg)O,TiO2; 
MnO,Ti02 ;      MgO,AlaO8 ;      (FeMg)O,Fe2O3 ;      FeO, 
Cr203. 


MOLECULAR  WEIGHTS  19 

38.  Mn203,H20;  (CaBa)CO3;  CaCO3,  (MgFe)CO3; 
KAlSi308;  (K2Ba)Al2Si4012  ;  (NaK)AlSi3O8. 

39.  CaAlSi2O8;        BaAl2Si2O8;       H2Cs4Al4(SiO3)9; 
NaFe(SiO3)2;   HNaCa2(SiO3)3  ;   (MnZnFeCa)SiO3. 

40.  (K2Na2MgCaMn)4(SiO3)4  ;  NaAl(SiO3)2, 
(FeMg)Si03  ;                              K2Na6Al8Si9O34  ; 

(NaK)10Ca4Al12Si12052SCl4. 

41.  Na4(NaS3,  Al)Al2(Si04)3  ;  Bi4(SiO4)3; 
Ca3Al2(SiO4)3  ;  (FeZnMn)2[(ZnFe)2S]Be3(SiO4)3; 

Ca3Cr2(Si04)3. 

42.  HCaBSiO6;    HBeAlSiO5;    Be2Fe(YO)2(SiO4)2  ; 
(CaFe)2(A10H)(AlCeFe)2(Si04)3  ;   CaB2(SiO4)2. 

43.  [Mg(FOH)]2Mg3(Si04)2  ;       (Na2Ca)Al2Si6O16, 
6  H20  ;  CaAl2Si3010,  5  H2O; 


44.  H2KAl3(SiO4)3  ;      KLi[Al(OHF)2]  Al(SiO3)3  ; 
[HK(MgFe)]3Mg3Al(Si04)3;   (PbCl)Pb4(VO4)3. 

45.  (MnOH)MnAs04;  (MgF)MgPO4; 
(PbZn)2(OH)V04  ;           (PbZnCu)2(OH)VO4; 

Zn3As2O8,  8H2O. 


CHAPTER   III 

Percentage  Composition 

1.  Find   per   cent   of   potassium   in    (#)   KBr ;   (5) 
KNO3 ;  O)  K2S04 ;  (d)  K2S. 

2.  Calculate  the  percentage  of  oxygen  by  weight  in 
mercuric  oxide,  manganese  dioxide,  potassium  chlorate, 
and  water. 

3.  In  borax  (Na2B4O7, 10  H2O)  find  the  percentage 
O)  of  B  ;   (6)  of  Na ;   (c)  of  O  ;   (d)  of  H2O. 

4.  Calculate  the  percentage  composition  of  CaCO3, 
CaC2,  CaCl2,  CO2,  MgCO3,  NaaCO8,  and  CO. 

5.  What  is  the  per  cent  of  tin  in  tinstone  (SnO2), 
in  SnCl4,  and  in  SnCl2  ? 

6.  Calculate  the  percentage  composition  of  the  fol- 
lowing compounds  : 

Potassium  ferrocyanide.     .     .     .     K4Fe(CN)6,  3  H2O. 

Iso-creatine C4H9N3O2. 

Rosaniline C20H21N3O. 

Strychnine C21H22N2O2. 

7.  The  skeleton  of  a   man  weighs  24  Ib.  and  con- 
tains 58  per  cent  of  calcium  phosphate  [Ca3(PO4)2]. 
Find  the  quantity  of  phosphorus  present. 

8.  How  much  phosphorus  can  be  obtained  from  169 
tons  of  bones  containing  53.7  per  cent  of  calcium  phos- 
phate ? 

20 


PERCENTAGE  COMPOSITION  21 

9.    Find  the  percentage  composition  of  crystallized 
hydrogen  disodium  phosphate  (Na2HPO4, 12H2O). 

10.  Find  the  per  cent  by  weight  of   the  elements 
called  for  in  the  following:   (#)  per  cent  of  oxygen  in 
HgO ;  (5)  of  hydrogen  in  HC1 ;   (<?)  of  lead  in  PbS ; 
(d)    of    lead  in   Pb(NO3)2;    (e)   of   each    element   in 
Ca3(P04)2. 

11.  Find  the  percentage   composition  of  H3PO4  to 
one  decimal  place. 

12.  Find  the  percentage  composition  of  ammonium 
nitrate. 

13.  A  sample  of  copper  salt  weighing  0.9864  g.  is 
dissolved  in  water  and  the  copper  deposited  electrolyt- 
ically.     The  weight  of  the  electrode  before  passing  the 
current  was   9.8609  g. ;   at  the  end   of   the  operation 
10.1121  g.     Find  the  per  cent  of  copper  in  the  sample. 

14.  Which  is  the  richer  in  iron,  Fe2O3  (hematite)  or 
Fe8O4  (magnetite)  ?     Compute. 

15.  Find    the    percentage    composition    of    alcohol, 
C2H60. 

16.  What  per  cent  of  sulphur  is  contained  in  pure 
pyrite  ? 

17.  Compute  the  percentage  composition  of  Fe3O4  to 
one  decimal  place. 

18.  Calculate  the  percentage  of  silica  in  potash  mica 
(KHAlSi04). 

19.  What  per  cent  of  silicon  is  in  quartz  ? 

20.  What  per  cent  of  magnesium  is  contained   in 
crystallized    potassium    magnesium    sulphate,     K2SO4, 
MgSO4,  6H2O? 


22        PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

21.  What  weight  of  potassium  can  be  obtained  from 
20  g.  of  alum  [K2A12(SO4)4,  24  H2O]  ? 

22.  Find   the   percentage    composition  of   bleaching 
powder  if  its  formula  is  Ca(OCl2). 

23.  100  g.   of  each  variety  of  sodium  carbonate  — 
(a)  Na2CO3,  10  H2O  ;   (ft)  Na2CO3,  8  H2O  ;   (c)  Na2CO3, 
5  H2O ;   (<T)    Na2CO3,  H2O  —  contain  how  many  g.  of 
water  ? 

24.  What  is  the  percentage  of  («)  barium  oxide  in 
wither! te;   (6)  strontium  oxide  in  strontianite;   (c)  zinc 
oxide  in  calamine  ? 

25.  Calculate    the    percentage    composition    of    the 
following  compounds:   carbon  dioxide  ;  ammonia  ;  ferric 
oxide  ;   acetic  acid  ;   calcium  sulphate  ;  cream  of  tartar  ; 
ferrous  sulphate;  common  alum. 

26.  Calculate    the   percentage    composition   of    cane 
sugar  and  of  glucose. 

27.  Calculate  the  percentage  of  water  of  hydration 
in  crystalline  cupric  sulphate. 

28.  What   are  the  percentage  compositions  of   sub- 
stances   possessing    the    following    formulas :     Mn3O4, 
NaCl,  and  SiF4  ? 

29.  Calculate  the  percentage  composition  of  propy- 
lene  (C3H6)  and  propane  (C3H8). 

30.  Find  the  per  cent  of  carbon  in  (CL)  CH4;  (b)  C2H2; 
00  C2H4;  09  COS;  («)  C4H10;  (/)  C6H10O5. 

31.  Calculate    the    percentage    composition    of    the 
following  compounds: 

Water,  Calcium  carbonate, 

Potassium  chlorate,  Silver  chloride, 

Mercuric  oxide,  Magnesium  pyrophosphate, 


PERCENTAGE  COMPOSITION  23 

Potassium  nitrate,  Potassium  platinum  chloride, 

Sodium  nitrate,  Sodium  thiosulphate, 

Barium  sulphate,  Magnetic  oxide  of  iron. 

32.  How  much  weight  will  32.2  g.  crystallized  sodium 
sulphate  lose  on  heating? 

33.  How  many  Ib.  of  dry  Na2CO3  is  contained  in  a 
Ib.  of  crystallized  washing  soda? 

34.  How  many  Ib.   of  plaster  of  Paris  can  be  made 
by  calcining  10  Kg.  of  gypsum  ? 

35.  What  is  the  percentage  of  sodium  in  Glauber's 
salt? 

36.  How  many  g.  of  C  and  of  S  are  contained  in 
1292  g.  of  CS2? 

37.  It  is  required  to  find  the  weight  of  iron  in  1000 
Kg.  of  ferric  oxide. 

38.  How  many  g.  of  copper  in   3   Kg.  of  Scheele's 
green  (CuHAsO3)? 

39.  What  weight  of  Ca,  P,  and  O  are  contained  in 
100  g.  bone  ash  ? 

40.  How  much  oxygen  in  10  g.  lime  ;  6  g.  litharge  ;  4 
g.  nitric  acid;  10  g.  sand? 

41.  How  many  g.  of  sodium  in  J  ton  of  NaNO3? 

42.  How  many  g.  of  mercury  in  20  g.  of  (#)  corrosive 
sublimate;   (£>)  26  g.  calomel;   (c)  13  g.   mercuric  sul- 
phide ? 

43.  How  much  sodium  in  (a)  10  g.  NaOH;   (6)  6  g. 
Na2S04;  <»  14  g.  NaCl;  (d)  2  g.  NaHSO4? 

44.  Find  the  percentage  composition  of  (CL)  galena; 
(&)  zinc  blende. 

45.  Find  the  percentage  composition  of  Cu(NO3)2; 
Pb(N03)2. 


24       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

46.  It  was  found  by  experiment  that  10  g.  of  crys- 
tallized sodium  sulphate  contained  4.70  g.  of  water; 
how  many  molecules  of  water  of  hydration  does  the 
crystallized  salt  contain? 

47.  What  is  the  percentage  of  copper  in  crystallized 
copper  sulphate? 

48.  What  is  the  percentage  of  nitrogen  in  "caliche" 
that  is  97.8  per  cent  pure? 

49.  A  room  15  ft.  long  and  10  ft.  wide  and  high  is 
covered  with  a  paper  containing  0.78  g.   of    Scheele's 
green   per   ft.2.     How   much   arsenic   is    there   in  the 
room  ? 

50.  How  many  g.  of  Pb  is  contained  in  each  of  the 
following:   (a)  10  g.  litharge;   (b~)  10  g.  minium;   (Y) 
10  g.  lead  peroxide  ? 

51.  Which  is  cheaper,  Na2B4O7, 10  H2O  at  7  cents  a 
pound,  or  the  anhydrous  salt  at  5  cents  a  pound  ? 

52.  How  many  Kg.   of  water  will  be  set  free  when 
1  ton  of  crystallized  copper  sulphate  is  converted  into 
the  anhydrous  condition  on  heating  ? 

53.  How   much   copper   in    (#)    10    g.    Cu2O ;     (5) 
13  g.  azurite  [2  CuCO3,  Cu(OH)2] ;  (<?)  2  g.  CuS  ? 

54.  What  is  the  weight  of  Ca  in   3  g.  of  calcium 
sulphate  ? 

55.  One  g.  of  soft  coal  on  analysis  gave  0.0593  g.  of 
barium  sulphate.     What  is  the  percentage  of  sulphur 
in  the  sample  of  coal  ? 

56.  How  much  arsenic  is  there  in  3  g.  of  magnesium 
arsenite  ? 

57.  Five  g.   of  galena  gave  on  analysis  5  g.  of  lead 
sulphate.     What  is  the  percentage  of  lead  ? 


PERCENTAGE  COMPOSITION  25 

58.  How  many  pounds  of  red  lead  can  be  made  from 
500  Ib.  of  litharge  ? 

59.  How  much  anhydrous  salt  in  a  Kg.  of  crystalline 
(a)  copper  sulphate ;   (6)    washing   soda ;   (c)    Epsom 
salts  ;  (d)  alum  ;  (e)  Glauber's  salt  ? 

60.  Find  the  g.  of  lead  in  (a)  21  g.  PbO2 ;  (6)  13  g. 
PbSO4;   (V)  14  g.  sugar  of  lead;   (d)  91  g.  cerussite 
(PbC03). 

61.  How   much    (1)    oxygen,   (2)    chlorine,  can  be 
obtained  from  100  g.  bleaching  powder  ? 

62.  How  many  pounds  of  phosphorus  in  265  pounds 
of  calcium  phosphate  ? 

63.  What  weight  of  barium  sulphate  can  be  obtained 
from  10  g.  of  crystallized  magnesium  sulphate  ? 

64.  Calculate  the  percentage  composition  of  Na2S2O3, 
5  H2O ;  find  the  number  of  g.  of  water  in  17  g.  of  the 
salt. 

65.  Find  the  percentage  of  hydrogen  in  (a)  HC1; 
(5)  H2S  ;  0)  NH3;   (d)  CH4 ;   (e)  HF. 

66.  KC1O3  is  39  <jo  oxygen  ;  calculate  the  g.  of  oxygen 
in  (a)  76  g. ;  (6)  276  g. ;  and  (c)  700  g. 

67.  A  sample  of  air  consists  of  12.37  g.  N  and  3.63 
g.  O.     Find  the  percentage  of  each. 


CHAPTER   IV 

Changes  in  Volume 

Due  to  (/)  changes  in  pressure  alone ; 

changes  in  temperature  alone; 

changes  in  both  temperature  and  pressure. 

I.    Changes  in  volume  due  to  difference  in  pressure. 

1.  The  pressure  on  134  cc.  of  air  is  increased  from 
480  mm.  to  1200  mm.     Find  the  new  volume. 

2.  The  pressure  of  240  cc.  of  nitrogen  is  increased 
from  720  mm.  to  780  mm.     Find  the  new  volume. 

3.  The  pressure  of  25  1.  HC1  is  decreased  from  863 
mm.  to  621  mm.     Find  the  new  volume. 

4.  The  pressure  of  15  1.  of  oxygen  is  increased  from 
700  mm.  to  800  mm.     Find  the  new  volume. 

5.  The  pressure  on  10  cc.  of  gas   is  7  m.  ;    if   the 
pressure  is  reduced  to  847  mm.,  what  is  the  new  vol- 
ume? 

6.  The  pressure  of  1000  cc.  of  a  gas  is  decreased 
from  774  mm.  to  600  mm.     Find  the  new  volume. 

7.  The  pressure  of  512  cc.  of  hydrogen  is  increased 
from  744  mm.  to  790.5  mm.     Find  the  new  volume. 

8.  The  barometric  pressure  of  5000  cc.  of  hydrogen 
is  increased  from  740  mm.  to  760  mm.     Find  the  new 
volume. 

26 


CHANGES   IN   VOLUME  27 

9.  Reduce  the  following  volumes  to  the  volume  oc- 
cupied at  standard  pressure  :  («)  221  cc.  at  963  mm. ; 
(ft)  30  cc.  at  662  mm.  ;  (V)  100  1.  at  1461  mm. 

10.  Under  standard  conditions  1  1.  of  oxygen  weighs 
1.4336  g. ;   what  is  the  pressure  when  1  1.  weighs  1.29  g. 

11.  Under  a  pressure  of  745  mm.  1500  cc.  of  a  gas 
weigh  1.9762  g.  ;    what   is   the   weight   per   1.   under 
standard  pressure? 

12.  A  body  of  gas  occupies  2000  cc.  when  the  ba- 
rometer stands  at  750  mm.     What  volume,  at  the  same 
temperature,  will  it  occupy  at  760  mm.? 

13.  I  have  4-|  1.  oxygen  under  a  pressure  of  750  mm. 
At  730  mm.,  what  space  will  it  fill? 

14.  At  850  mm.,  what  should  be  the  volume  of  a  gas 
which  at  600  mm.  fills  100  cc.  ? 

15.  What  volume  will  the  same  gas  occupy  at  200 
mm.  pressure? 

16.  One  1.  of  air  at  normal  pressure  and  temperature 
weighs  1.293  g.     Under  what  pressure  will  the  same 
volume  weigh  2  g.  ? 

17.  CO  has  a  volume  of  18  1.  at  a  pressure  of  500 
mm.     Find  volume  at  650  mm. 

18.  If  27  1.  of  gas  at  690  mm.  now  occupy  31  1., 
what  is  the  new  pressure? 

19.  A  balloon  containing  1200  cm.3  of  coal  gas  under 
a  pressure    of    770    mm.  ascends  until  the   barometer 
stands  at  530  mm.     What  volume  would  the  gas  in  the 
balloon  now  occupy,  supposing  none  to  have  escaped  ? 

20.  A  certain  volume  of  air  preserved  at  a  constant 
temperature    measures    150    cc.    when  the    barometer 
stands  at  760  mm.     On  the  following  day  its  volume 


28       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

is  found  to  have  decreased  1.52  cc.  Calculate  the  al- 
teration in  the  height  of  the  barometer  which  must 
have  ensued. 

21.  What  will  be  the    excess    of   pressure  inside  a 
bottle  of  soda  water  when  four  volumes  of  carbon  di- 
oxide are  dissolved  in  one  volume  of  water? 

22.  A  volume  of  hydrogen  measuring  195  cc.  when 
the  barometer  stood  at  740  mm.  was  afterward  found 
to  measure  200  cc.     What  was  the  height  of  the  ba- 
rometer at  that  time  ? 

23.  A  flask  having  a  capacity  of  4.5  1.  is  filled  with 
a  gas  when  the  barometer  stands  at  755  mm.     What 
would  be  the  volume  of  the  same  gas  in  cc.  when  the 
barometer  stands  at  762  mm.  ? 

24.  A  volume  of  hydrogen  in  a  bell  jar  over  mercury 
measured  524  cc.     The  mercury  in  the  jar  was  54  mm. 
above  the  surface  of  the  mercury  in  the  trough,  and  the 
barometer  stood  at  745  mm.      What  would  have  been 
the  volume  if  exposed  to  the  standard  pressure  alone? 

25.  A  volume  of  gas  was  found  to  be  equal  to  250 
cc.  when  the  height  of  the  barometer  was  742  mm. 
What  would  have  been  the  volume  had  the  barometer 
stood  at  760  mm.  ? 

26.  A  volume  of  gas   measured  467   cc.    when  the 
barometer   stood   at   756  mm.     What   would   it   have 
measured  had  the  barometer  stood  at  760  mm.  ? 

27.  A  volume   of  air  measured    137    cc.    when    the 
barometer   stood   at    766   mm.      What  would  it  have 
measured  had  the  barometer  stood  at  757  mm.  ? 

28.  If  a  certain  mass  of  gas  occupies  800  cc.  at  a 
pressure  of  76  cm.,  what  would  its  volume  be  at  74  cm. 
pressure  ? 


CHANGES  IN  VOLUME  29 

29.  Into   what   space  must   60  ft.3  of   air  be   com- 
pressed that  its  expansive  force  may  be  made  twelve 
times  as  great  ? 

30.  How  strong  would  a  compression  tank  have  to 
be  if  its  capacity  is  600  in.3  and  5  ft.3  of  air  at  normal 
pressure  is  forced  into  it  ? 

31.  What  will  be  the  weight  of  a  1.  of  air  under  a 
pressure  of  300  in.  of  mercury  ? 

32.  A  rectangular  diving  bell  14  ft.  high  is  sunk  to 
the  bottom  of  a  lake  at  a  point  where  the  water  is  60 
ft.  deep.     Find  how  high  the  water  will  rise  in  the  bell. 

II.     Volume  with  temperature  alone  changing. 

33.  If  170  volumes  of  oxygen  are  measured  at  -f-  10°  C., 
what  will  the  volume  be  when  the  temperature  falls  to 
0°C.? 

34.  If  10  cc.  of  a  gas  are  measured  at  +  15°  C.,  what 
volume  will  the  gas  occupy  at  +  150°  C.  ? 

35.  If  100  cc.  of  hydrogen  are  measured  at  +  200°  C., 
how  many  cc.  will  the  gas  occupy  at  —  200°  C.  ? 

36.  Calculate  the  temperature  at  which  air  possesses 
a  density  equal  to  that  of  hydrogen  at  0°  C. 

37.  A  mass  of  gas  at  0°C.  measures  2000  cc.     Find 
the  volume  at  (a)  -  7°  C.  ;   (ft)  +  10°  C.  ;   (c)  +  27°  C.  ; 
(d)  +  106°C.;   <V)-230C. 

38.  An  open  vessel  was  heated  until  one-third  of  the 
air  it  contained  at  0°  C.  was  driven  out ;    how  much 
was  it  heated  ? 

39.  How  much  must  a  1.  of  air  at  +  10°  C.  be  heated 
in  order  to  increase  its  volume  two-thirds  ? 


30       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

40.  At  what  temperature  would  nitrogen  have  the 
same  density  that  hydrogen  has  at  0°  C.  ? 

41.  What  will  be  the  volume  of  250  cc.  of  hydrogen 
measured  at  +  30°  C.  when  cooled  to  -  10°  C.  ?  " 

42.  What  will  be  the  volume  at  +  25°  C.  of  252  cc.  of 
oxygen  measured  at  +  15°  C.  ? 

43.  If    170    volumes    of    oxygen    are    measured    at 
+  10°C.,  what  will  the  volume  be  if  the  temperature 
falls  to  0°  C.  ? 

44.  When  600  cc.  of  oxygen  at  +  21°  C.  are  cooled  to 
—  8°  C.,  what  is  the  new  volume  ? 

45.  A  certain  weight  of  air  measures  a  1.  at  0°  C. ; 
how  much   will  the   air   expand   on    being   heated  to 
+ 100°  C.  ? 

46.  What  is  the  temperature  when  15  1.  of  a  gas  at 
+  20°  C.  will  occupy  a  volume  of  18.6  1.  ? 

47.  A  flask  holding  600  cc.  of  air  at  0°  C.  is  heated  to 
H-  25°  C. ;  what  volume  of  expanded  air  escapes  ?     Tem- 
perature of  escaped  air  is  +  25°  C.     Neglect  expansion 
of  flask. 

48.  A  volume  of  gas  measuring  500  cc.  at  0°  C.  was 
expanded  by  heating  to  600  cc.  at  constant  atmospheric 
pressure ;  what  temperature  did  the  gas  attain  ? 

49.  A  rubber  balloon  containing  400  cc.  of  oxygen 
measured  at  —  20°  C.  is  subjected  to  a  temperature  of 
-h 120°  C.     What  is    the    increase    in    volume    of   the 
balloon  ? 

50.  At  what  temperature  will  1  1.  of  chlorine  weigh 
the  same  as  1  1.  of  hydrogen ;   1  1.  of  N2O  ;   1 1.  of  NH3? 

51.  If  100  cc.  of  a  gas  at  +10°  C.  is  found  to  change 
its  volume  to  110  cc.,  at  what  temperature  is  it  then? 


CHANGES   IN   VOLUME  31 

52.  The   temperature    of   a   gas   being   raised   from 
-  15°  C.  to  +10°  C.,  it  now  measures  200  cc.     Find  the 
original  volume. 

53.  What   volume   will    1000  cc.   of   air   at+13°C. 
occupy  at  +65°  C.  ? 

54.  If   300  cc.  of   gas  are  measured  off  at+28°C., 
what  will  the  volume  become  at  —  14°  C.  ? 

55.  A  1.  of  gas  is  heated  from  + 14°  C.  to  +  42°C. 
Find  the  new  volume. 

56.  A  1.  of  air  at  +  39°  C.  is  cooled  to  -  26°  C.     Find 
the  new  volume. 

57.  What  volume  will  50  cc.  of  gas  at  + 10°  C.  occupy 

at+24°C.? 

58.  If  100  cc.  of  air  at  +12°  C.  are  heated  until  they 
occupy  145  cc.,  what  is  the  new  temperature  ? 

59.  A  volume  of  air,  measuring  230  cc.,  was  standing 
in  a  1.  flask  over  water,  the  temperature  of  which  was 
+  26°  C.     The  temperature  was  then  raised  to  +60°C. 
How  much  water  then  remained  in  the  flask? 

60.  I  have  a  1.  flask  full  of  hydrogen  at  +  15°C.     I 
wish  to  expel  half  the  gas.     To  what  temperature  must 
it  be  heated  ? 

61.  I  have  a  1.  flask  full  of  oxygen  standing  over 
water  at  +90°C.     I  wish  100  cc.  of  water  to  enter  the 
flask.     What  must  be  the  temperature? 

62.  3  1.  of  chlorine  and  5  1.  of  hydrogen  were  mixed 
and  exposed  to  sunlight  at  a  temperature  of  -f  15°  C. 
It  was  found,  after  the  HC1  had  been  formed,  that  the 
temperature  had  risen  to  +  40°  C.     What  volume  did 
the  gases  then  occupy? 


32       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

63.  Below +500°  C.   sulphur   has   six  atoms  to  the 
molecule ;  above  4-500°  C.  it  has  only  two  atoms  to  the 
molecule.     We  have  300  cc.  of  sulphur  gas  at  +450°  C. 
What  will  be  the  volume  at  +  800°  C.  ? 

64.  If  1000  cc.  of  gas  are  heated  from  0°  C.  to  +  39°  C., 
what  is  the  new  volume  ? 

65.  If  1000  cc.  of  gas  are  heated  *from+39°C.  to 
+  52° C.,  what  is  the  new  volume? 

66.  What  volume  will  20  ft.3  of  air  at  -7°  C.  have 

at+7°C.? 

67.  If  the  vapor  density  of  a  gas  is  32  at  the  temper- 
ature of  -f-15°C.,  at  what  temperature  will  it  have  a 
vapor  density  of  28.16? 

68.  A  quantity  of  gas  was  measured  when  its  tem- 
perature was  +  12  °C.    At  what  temperature  would  its 
volume  be  doubled? 

69.  An  open  vessel  was  heated  to  +  819°  C.     What 
portion  of  the  air  that  the  vessel  contained  at  0°  C.  re- 
mained in  it? 

70.  An  open  vessel  was  heated  till  l  of  the  gas  that 
it  contained  at  +  15°  C.  was  driven  out.    What  was  the 
temperature  of  the  vessel? 

71.  A  volume  of  air  measured  475  cc.  at  +  27°  C. 
What  would  have  been  its  volume  at  0°  C.  ? 

72.  A  quantity  of  hydrogen  measured   550   cc.    at 
4- 15°  C.     What  would  have  been  its  volume  had  its 
temperature  been  —10°  C.  ? 

73.  A   given  weight   of    air    measured    256  cc.    at 
+  34°  C.    What  would  have  been  its  volume  had  its 
temperature  been  0°  C.  ? 


CHANGES   IN   VOLUME  33 

74.  A  volume  of  nitrogen  measured  3.5  1.  at  -f-  75°  C. 
What  would  have  been  its  volume  had  its  temperature 
been  + 15°  C.  ? 

75.  A  volume  of  gas  measured  50  cc.  at  -h  15°  C.    At 
what  temperature  would  its  volume  be  44  cc.  ? 

76.  What  volume  will  400  1.  of  illuminating  gas  at 
+  60°  C.  occupy  at  +  22°  C.,  if  there  is  no  change  of" 
pressure  ? 

77.  If  100  cc.  of  hydrogen  are  measured  at  4- 100°  C., 
how  many  cc.  will  the  gas  occupy  at  —100°  C.  ? 

78.  What  volume  will  1000  cc.  of  hydrogen  at  0°  C. 
occupy  at  (a)  +  15°  C.  ;   (6)  +  20°  C. ;    (e?)  +  300°  C.  ? 

79.  A  gas  has  its  temperature  raised  from  +19°  C.  to 
+  50°  C.  ;  at  the  latter  temperature  it  measures  15  1. 
What  was  the  initial  volume  ? 

80.  A  certain  weight  of  air  measures  a  1.   at  0°  C. 
How  much  will   the   air  expand  on  being  heated  to 
+ 100°  C.  ? 

81.  A  volume  of  hydrogen  measures  1500  cc.  at  0°  C. 
How  many  cc.  will  it  measure  at  (#)  +  15.5°  C.  ;   (5)  at 
+  50°  C. ;   (<?)  at  +400°  C.  ;    (d)    at  +600°C.?     At 
what  temperature  will  it  measure  exactly  1000  cc.  ? 

82.  If  10  cc.  of  a  gas  are  measured  at  +  18°  C.,  what 
volume  will  the  gas  occupy  at  +  150°  C.  ? 

83.  Calculate  the  temperature  at  which  air  possesses 
a  density  equal  to  that  of  methane  at  0°  C. 

84.  If  the  sp.  gr.  of  air  at  -f  20°  C.  normal  pressure 
is  0.00118,  what  will  be  the  weight  of  a  1.   of  air  at 
-  20°  C.  ? 

85.  A  volume  of  air  at  0°  C.  measures  1  1. ;  what  will 
be  its  volume  at  +  18°  C.  ? 


34       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

86.  A  volume   of  air  at  +  91°  C.  measures  1000  cc. 
Reduce  the  volume  to  standard  temperature. 

87.  An  open  vessel  is  heated  from  0°  C.  to  +  546°  C. 
What  portion  of  the  air  that  it  at  first  contained  now 
remains  ? 

88.  Find  the  volume  of  the  following  at  0°  C.  :   (a) 
"170  cc.  at  +  13°  C.  ;   (5)  400  cc.  at   +  14°  C. ;    (<?)  771 
cc.  at  +1°   C.  ;   (d)  288  cc.  at  -  7°  C. ;   <»  300  cc. 
at  +  200°  C. 

89.  A  1.  flask  filled  with  air  at  — 10°  C.  is  heated  to 
+  70°  C.      What  will  be  the   volume   of  the   air  that 
escapes  if  measured  at  0°  C.  ? 

III.    Volume  with  pressure  and  temperature  both  changed. 

90.  Given  800  cc.  of  nitrogen   at  --  1°  C.  and  721 
mm.,  what  will  be  the  volume  at  +  1°  C.  and  ^  an  at- 
mosphere pressure  ? 

91.  A  certain  quantity  of  nitrogen  measures  155  cc. 
at  + 10°  C.  and  under  a  pressure  of  530   mm.     What 
will  the  volume  become  at  +  18.7°  C.  and  under  a  pres- 
sure of  590  mm.  ? 

92.  A  volume  of  hydrogen  at  a  temperature  of  +  15° 
C.  measured  2.7  1.  when  the  barometer  stood  at  752mm. 
What  would  have  been  its  volume  had  its  temperature 
been  +  9°  C.  and  the  barometer  stood  at  762  mm.? 

93.  Given  18  cc.  gas  at  +  16°  C.  and  772  mm.,  what 
will  be  the  volume  at  0°  C.  and  760  mm.  ? 

94.  Given  14  cc.  gas  at  +  11°  C.  and  900  mm.,  what 
will  be  the  volume  at  +  3°  C.  and  790  mm.  ? 

95.  Given  2.7  1.  at  +  18°  C.  and  749  mm.,  what  will 
be  the  volume  at  0°  C.  and  760  mm.  ? 


CHANGES   IN   VOLUME  35 

96.  Given  500  cc.  of  a  gas  at   +163°  C.  and  8.72 
mm.,  find  its  volume  at  +  77°  C.  and  10  mm.  • 

97.  A  volume   of   air  at  standard  temperature  and 
pressure  is  compressed  to  J  its  original  volume,  and  the 
temperature  is  then  raised  to  +  25°  C.     What  will  now 
be  the  pressure  in  atmospheres? 

98.  If  1500  cc.  of  nitrogen  at  +57°  C.  and  780  mm. 
are  cooled  to  +  27°  C.,  the  pressure  being  decreased  to 
740  mm.,  what  is  the  new  volume? 

99.  Given  500  cc.  of  hydrogen  at   +  25°  C.  and  760 
mm.  pressure,  what  will  be  the  volume  at  -f  115°  C.  and 
755mm.? 

100.  I  fill  a  flask  of  2  1.  capacity  with  hydrogen  when 
the  thermometer  indicates  +  25°  C.  and  the  barometer 
762  mm.     What  is 'the  volume  at  0°  C.  and  760  mm.? 

101.  I  measure  a  volume  of  nitrous  oxide  at  755  mm. 
and  -f  17°  C.,  and  find  360  cc.     What  volume  should  it 
occupy  at  960  mm.  and  +  37°  C.  ? 

102.  Compute  the.  volume  of  carbon  dioxide  at  300 
mm.  and  +  50°  C.  which  is  25  1.  at   +  20°  C.  and  700 
mm. 

103.  A  certain  mass  of  gas  measures  11,000  gal.  at 
+  14°  C.  and  740  mm.  pressure.     To  what  volume  will 
it  expand  when  the  temperature  reaches  +  27°  C.  and 
the  pressure  620  mm.  ? 

104.  If  100  1.   of  gas  at   +  30°  C.    and  731  mm.   is 
cooled  to  -f  25°  C.  while  the  pressure  rises  to  790  mm., 
and  is  then  measured  again,  what  is  its  new  volume  ? 

105.  Given  500  1.  of  ammonia  gas  at  +  135°  C.  and 
752  mm.,  what  will  be  its  volume  at  +  100°  C.  and  760 
mm.  ? 


36       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

106.  Given  730  cc.  of  nitrogen  at  +  25°C.  and  770 
mm.,  what  will  be  the  volume  of  this  mass  of  gas  at 
-  30°  C.  and  710  mm.  ? 

107.  A  quantity  of  illuminating  gas  measures  5  1. 
and  25  cc.  at  + 17°  C.  and  760  mm.     What  will  be  its 
volume  at  +  100°  C.  and  735  mm.  ? 

108.  If  175  cc.  of  gas  are  measured  at  +  20°  C.  and 
785  mm.,  what  would  be  the  volume  of  the  same  mass 
of  gas  at  0°  C.  and  760  mm.  ? 

109.  Given  125  cc.  of  gas  at  +1°C.  and  750mm., 
what  will  be  the  volume  at  0°  C.  and  650  mm.  ? 

110.  Given  40  pt.  of  gas  at  +  10°  C.  and  740  mm., 
what  is  the  volume  at  —  10°  C.  and  630  mm.  ? 

111.  Given  1  ft.3  of  gas  at  — 110°  C.  and  510  mm., 
what  is  the  volume  at  +  25°  C.  and  820  mm.  ? 

112.  Given  1  gal.  of  gas  at  -f-  21°  C.  and  722  mm., 
what  is  the  volume  at  0°  C.  and  760  mm.  ? 

113.  Given  300  1.  of  gas  at  -  100°  C.  and  310  mm., 
what  is  the  volume  at  0°  C.  and  760  mm.? 

114.  Given  22.16  m.3  of  gas  at  0°C.  and  760  mm., 
what  is  the  volume  at  +  25°  C.  and  750  mm.  ? 

115.  Given  0.18  1.  of  gas  at  0°  C.  and  760  mm.,  what 
is  the  volume  at  —  25°  C.  and  770  mm.  ? 

116.  If  a  room  measures  10  m.  by  100  dm.  by  1000 
cm.,  what  volume  of  air  will  escape  from  it  if  the  tem- 
perature changes  from  —11°  C.  to  —15°  C.  ?    What  vol- 
ume if  the  pressure  changes  from  760  mm.  to  735  mm.  ? 
What  volume  if  both  temperature  and  pressure  change 
together  ? 

117.  What  mass  of  oxygen  at  +  10°  C.  and  750  mm. 
would  fill  a  globe  of  16  1.  capacity  ? 


CHANGES  IN   VOLUME  37 

118.  If  the  volume  of  a  mass  of  ammonia  is  500  cc. 
at   +  40°C.  and  under  the  pressure,  of  60  mm.,  what 
would  it  be  under  the  pressure  of  35  mm.  at  +  20°  C.  ? 

119.  If  the  volume  of  a  mass  of  nitrogen  is  50  cc.  at 
-f-  20°  C.  and  under  the  pressure  of  60  cm.,  what  would 
it  be  under  the  pressure  of  900  mm.  at  +  100°  C.? 

120.  If  the  volume  of  a  mass  of  carbon  dioxide  is 
2050  cc.  at  +200°C.  and  under  the  pressure  of  5  cm., 
what  would  be  the  volume  in  1.  under  the  pressure  of 
400  mm.  at  +  50°  C.  ? 

121.  If  the  volume  of  a  mass  of  steam  is  50,000  cc. 
at  200°  C.  and  under  the  pressure  of  1200  cm.,  what 
would  be  the  volume  in  1.  under  the  pressure  of  20,000 
mm.  at  +  250°  C.  ? 

122.  If  470  cc.  of  nitrous  oxide  at  +  40°  C.  stand  in 
a  tube  over  mercury,  the  level  within  the  tube  being  70 
mm.  above  that  without,  and  the  barometric  pressure 
being  740  mm.,  what  would  be  the  volume  of  the  gas  at 
+  15°C.,  the  barometric  pressure  being  765  mm.  and 
the  level  within  the  tube  being  20  mm.   below  that 
without  ? 

123.  If  1  1.  of  carbon  dioxide  at  -f 18°  C.  stand  in  a 
tube  over  mercury,  the  level  within  the  tube  being  125 
mm.  below  that  without,  and  the  barometric  pressure 
being  755  mm.,  what  would  be  the  volume  of  the  gas  at 
H-  50°  C.,  the  barometric  pressure  being  74  cm.  and  the 
level  within  the  tube  being  500  mm.  above  that  with- 
out? 

124.  If  300  cc.  of  air   at   +20°C.  stand  in   a  tube 
over  mercury,  the  level  within  the  tube  being  20  cm. 
above  that  without,  and  the  barometric  pressure  being 
750  mm.,  what  would  be  the  volume  of  the  gas  at 


38       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

-j-100°C.,  the  barometric  pressure  being  760  mm.  and 
the  level  within  the  tube  being  70  cm.  above  that  with- 
out ? 

125.  If  the  pressure  of  300  cc.  of  gas  is  600  mm.  at 
+  5°C.,  what  pressure  would  be  required  to  maintain 
the  volume  at  350  cc.  at  +  100°  C.  ? 

126.  What  volume  will  30  g.  of  oxygen  occupy  at 
4-  200°  C.  under  the  pressure  of  80  cm.  of  mercury  ? 

127.  At  what  temperature   will   J    Kg.    of  sulphur 
dioxide  have  a  volume  of  40  1.  under  5  atmospheres 
pressure  ? 

128.  How  many  g.  of  nitrous  oxide  will  occupy  900 
cc.  under  the  pressure  of  2  atmospheres  at  4-  50°  C.  ? 

129.  If  320  cc.  of  gas  are  measured  at  +  91°  C.  and 
950  mm.,  what  is  the  normal  volume  ? 

130.  If  542  cc.  of  air  at  +269°C.  and  900  mm.  are 
cooled  to  +  51°  C.,  the  pressure  being  decreased  to  666 
mm.,  what  is  the  new  volume  ? 

131.  If  546  cc.  of  gas  at  +  17°C.  and  760  mm.  are 
cooled  to  0°C.,  the  pressure  being  decreased  to  600 
mm.,  what  is  the  new  volume  ? 

132.  A  quantity  of  oxygen  which  measures  230  1.  at 
+  14°  C.  and  740  mm.  will  measure  how  much  at  0°  C. 
and  760  mm.  ? 

133.  If  1234  cc.  of  normal  gas  are  cooled  to  —  52°  C., 
the  pressure  being  decreased  to  617  mm.,  what  is  the 
new  volume  ? 

134.  The  volume  of  a  gas  contained  in  a  tube  measures 
86  cc.,  the  mercury  standing  at  a  height  of  34  mm.   in 
the  tube.     Barometric  pressure  is  742  mm.  ;  temperature 
is  +  23°  C.     What  is  the  normal  volume  of  the  gas? 


CHANGES   IN   VOLUME  39 

135.  One  1.  of  oxygen  at  0°  C.   and  760  mm.   pres- 
sure weighs   1.4296  g.       What    will    it   weigh   at   the 
same  temperature  with  the  barometer  standing  at  780 
mm.  ? 

136.  What  will  be  the  weight  of  300  cc.  of  oxygen  at 
+  18°  C.  and  with  the  barometer  at  730  mm.  ? 

137.  Under  standard  pressure  at  what  temperature 
will  1  1.  of  oxygen  weigh  1  g.  ? 

138.  What  will  be  the  volume  of  200  g.  of  oxygen  at 
770  mm.  pressure  and  +  27°  C.  ? 

139.  A    volume   of  hydrogen  measuring  500  cc.  at 
+  25°  C.  and  730  mm.  was  reduced  in  volume  to  400  cc. 
at  0°  C.     What  was  the  final  pressure  of  the  gas? 

140.  If  150  cc.   of  air    are  measured  over  water  at 
4- 18°  C.   and    746  mm.    pressure,    what    will    be    the 
volume  at  standard  conditions? 

141.  Since    1   1.    of   oxygen  at  standard  conditions 
weighs  1.429  g.,    440  cc.  of   this  gas    measured  over 
water  at  +  24°  C.   and  742  mm.   pressure  will  contain 
what  weight  of  the  dry  gas  ? 

142.  What  increase  in  pressure  is  necessary  to  force 
100  cc.   of    hydrogen  at  -f  46°  C.  and  740  mm.  into  a 
vessel  of  80  cc.  capacity,  when  the  temperature  of  this 
vessel  is  constant  at  0°  C.  ? 

143.  Find  volume  under  standard  conditions  of  a  mass 
of  oxygen  occupying  75  cc.   at  +  40°  C.  and  750  mm. 
pressure. 

144.  Chlorine  occupies  20  1.  at  720  mm.  and  -f  20°  C. 
Find  volume  when  conditions  change  to  790  mm.  and 
+  30°  C. 


40       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

145.  A  flask  of  air  at  standard  conditions  weighs  26 
g.     What  capacity  must  it  be,  when  filled  with  oxygen 
at  +  14°  C.  and  753  mm.,  to  weigh  26.73  g.  ? 

146.  The  conditions  in   a  vessel  are   +11°  C.    and 
800  mm.     What  expansion  would  there  be  if  the  tem- 
perature   changed  to  -+-100°C.    and    the   pressure    to 
766  mm.  ? 

147.  A  cylinder  contains  air  at  +  5°  C.  and  4  atmos- 
pheres pressure.     Show  that  if   the  air  is  heated  to 
+  565°  C.  the  cylinder  must  be  able  to  stand  a  pressure 
of  over  12  atmospheres  in  order  not  to  break. 

148.  A  1.  of  air  is  measured  at    0°C.  and  760  mm. 
What  volume  will  it  occupy  at  740  mm.  and  +  15.5°  C.  ? 

149.  Given     375   cc.     of   oxygen   at    -fl7°C.    and 
375mm.,  what  will  be  the  volume  at  standard  condi- 
tions ? 

150.  Given  3  1.  hydrogen  at  +  15°  C.   and  752  mm., 
what  will  be  the  volume  at   +  9°  C.  and  763  mm.  ? 

151.  What  is  the  sp.  gr.  of  oxygen  when  the  barom- 
eter stands  at  760  mm.   and  its  temperature  is  0°  C.,  if 
its  sp.  gr.  is  14.7648  when  the  barometer  stands  at  745 
mm.  and  its  temperature  is  +  17°  C.  ? 

152.  What  decrease  in  pressure  will  be  necessary  to 
raise  a  volume  of  gas  measuring  over  water  400  cc.,  at 
+  22.5°  C.  and  748  mm.  pressure,  to  a  volume  of  440  cc. 
under  the  same  conditions? 

153.  What  increase  in  atmospheric  pressure  will  be 
necessary  to  reduce  200  cc.  of  a  gas,  measured  in  a  tube 
over  water  at  +  10°  C.  and  720  mm.,  to  a  volume  of 
100  cc.  at  +  20°  C.  in  this  same  tube  ? 


CHANGES  IN  VOLUME  41 

154.  If  98  1.  of  hydrogen  are  to  be  admitted  into  a 
balloon  at  a  temperature  of  +  20°  C.  and  a  pressure  of 
740  mm.,  what  must  be  the  capacity  of  the  balloon? 

155.  Of  what  capacity  is  that  vessel  which  contains 
4  Kg.  of  oxygen  at  the  temperature  of  +18°  C.  and  a 
pressure  of  748.4  mm.  ? 

156.  If  110.08  HI.  of  hydrogen  at  0°  C.  and  760  mm. 
pressure   are   to   be    forced    into   a   vessel    of   11.2   1. 
capacity,  under  what  pressure  will  the  hydrogen  be  at 
this  same  temperature  ? 

157.  What  volume  will  0.8  g.  of  hydrogen  occupy 
at  + 100°  C.  under  the  pressure  of  750  mm.  of  mer- 
cury ? 

158.  What  pressure  will  be  exerted  by  10  g.  of  car- 
bon monoxide,  the  volume  of  which  is  15  1.  at  +20°  C.  ? 
(11.  =  1.261  g.) 

159.  At  what  temperature  will  20  g.  of  nitrous  oxide 
fill  a  space  of  8000  cc.  under  twice  the   atmospheric 
pressure?     (1  1.  =1.969  g.) 

160.  What  is  the  weight  of  51.  of  oxygen  under  the 
pressure  of  800  mm.  of  mercury  at  +40°  C.? 

161.  What  will  be  the  pressure  of  10  g.  of  marsh 
gas,  the  volume  of  which  is  15  1.  at  +  30°  C.  ?     (11.= 
0.716  g.) 

162.  If  a  certain  volume  of  gas  weighs  5  g.  at  +  50°  C. 
and  300  mm.,  what  should  a  like  volume  of  the  same 
gas  weigh  if  measured  at  -+-  35°  C.  and  500  mm.? 

163.  A  volume  of  chlorine  measured  at  +  18°  C.  and 
756  mm.  weighs  3  g.     If  the  same  volume  had  been 
found  at  +36°  C.  and  700  mm.,  what  would  it  have 
weighed?     (1  1.  Cl  =  3.167  g.) 


42       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

164.  Carbon  dioxide  at  N.T.P.  weighs  1.98  g.  per  1. 
What  would  a  1.  of  it  weigh  at  +  30°  C.  and  800  mm.  ? 

165.  What  is  the  volume  of   20  g.  of   ammonia  at 
+  12°  C.  and  730  mm.  ?     (11.=  O.T6  g.) 

166.  If  146  1.  of  nitrogen  at  +  17°  C.  and  974  mm. 
are  heated  to  +  51°  C.,  the  pressure  being  decreased  to 
760  mm.,  what  is  the  new  volume  ? 

167.  What  is  the  mass  of  270  cc.  of  nitrogen  meas- 
ured over  water  at   4-8°  C.  and  768  mm.?     (1  1.   = 
1.25  g.) 

168.  A  gas  measured  over  water   has  a  volume   of 
64.2  cc.  at  +18.6°  C.  and  742.5  mm.     Find  what  the 
volume  would  be  at  0°  C.  and  760  mm. 

169.  Given  400  cc.  of  oxygen  at  standard  conditions, 
what  will  -be  the  volume  when  measured  over  water  at 
+  20°  C.  and  755  mm.  pressure? 

170.  Given  100  cc.  of  a  gas  measured  over  water  at 
4-  25°  C.  and  745  mm.  pressure,  what  will  be  the  vol- 
ume when  deprived  of  moisture  ? 

171.  Given  1000  cc.  of  oxygen  measured  over  water 
at  4-  10°  C.  and  750  mm.  pressure,  what  will  be  the 
volume  at  —  10°  C.  and  770  mm.  pressure   when  de- 
prived of  moisture? 

172.  Given  500  cc.  of  a  gas  contained  in  a  tube  in- 
verted  over   water,    and   measured   at    + 10°    C.    and 
765  mm.  pressure,  what  will  be  the    volume  under  a 
change  in  the  atmospheric  conditions  to  +  20°  C.  and 
745  mm.  pressure? 

173.  A  vessel  of   2000  cc.    capacity  held  5  g.   of  a 
vapor  at  the  standard  conditions  of   temperature  and 
pressure.     What  weight  of  this  vapor  at  +  10°  C.  and 


CHANGES  IN   VOLUME  43 

750  mm.  pressure  can  be  held  in  this  vessel,  the  capac- 
ity considered  constant? 

174.  Reduce  the  following  to  standard  conditions : 
(a)  150  cc.  at  603  mm.  and  +  31°  C ;   (5)  400  cc.  at 
876  mm.   and   -  9°  C. ;   (c)  500  cc.  at  371  mm.  and 
4-62.17°  C.  ;  (d)    20  cc.  at  700  mm.  and  -14°  C. ; 
0)  7  1.  at  1376  mm.  and   +13°  C. 

175.  A  certain  volume  of  gas  is  enclosed  in  a  vessel 
at  76  cm.  pressure  and  —  20°  C.     It  is  then  heated  to 
-f-  40°  C.     What  is  the  pressure  on  the  sides   of   the 
vessel  measured  in  terms  of  the  atmosphere? 

176.  If  1000  cc.  of  chlorine  at  +  46°  C.  are  in  a  tube 
over  mercury  which  stands  in  the  tube  39  mm.  above 
that  without,  the  pressure  outside  being  750  mm.,  what 
would  be  the  volume  of  the  gas  under  standard  condi- 
tions? 

177.  The  air  in  a  flexible  rubber  bag  is  found  to  oc- 
cupy a  volume  of  1  ft.3  at  30  in.  pressure  and  +20°  C. 
If  the  bag  is  plunged  to  a  depth  of  170  ft.  in  water,  the 
temperature  of  which  is  +  10°  C.,  what  will  be  its  vol- 
ume? 

178.  A  vessel  full  of  air  at  0°  C.  is  heated  to  +  80°  C., 
when  2  cc.  of  the  air  measured  at  0°  C.  are  found  to 
have  escaped.     How  much  air  was  in  the  vessel  before 
heating  ? 

179.  A  1.  of  chlorine  at  0°  C.  and  76  cm.  pressure 
weighs  3.167  g.     If  the  pressure  is  decreased  to  74  cm., 
what   must  the  temperature  be  that  a  1.  of   gas  may 
weigh  2  g.  ? 

180.  If  a  1.  of  nitrogen  at  0°  C.  and  76  cm.  pressure 
weighs  1.25  g.,  how  many  1.  at   +25°  C.  and  74  cm. 
pressure  will  be  required  to  weigh  8  g.  ? 


44       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

181.  Find  the  volume  of  4450  cc.  of  carbon  dioxide, 
measured  at  standard  conditions,  at  890  mm.  pressure 
and  +  27°  C. 

182.  A  1.  of  hydrogen  at  760  mm.  pressure  and  0°  C. 
weighs  0.0899  g.     What  will  10  1.  weigh  at  -  20°  C. 
and  750  mm.  pressure? 

183.  At  what  temperature,  when  under  a  pressure  of 
75  cm.,  will  2  1.  of  gas  measured  at  +  46°  C.  and  76  cm. 
pressure  measure  1.8  1.  ? 

184.  A  gas  at  0°  C.  and  760  mm.  pressure  measured 
250  cc.     What  will  it  measure  at  -10°  C.  and  760  mm. 
pressure  ? 

185.  A  volume  of  gas  in  a  eudiometer  measures  242 
cc.     The   mercury  in   the   tube  stands    18  cm.   above 
that   outside.     Barometer   at    740  mm. ;    temperature, 
+  18°  C.     Reduce  to  standard  volume. 

186.  A  volume  of  gas  in  a  tube  measures  72  cc.     The 
mercury  in  the  tube  stands  at  the  same  level  as  that  on 
the  outside.    Barometer  737mm.;  temperature  +17°C. 
What  would  be  the  volume  under  standard  Conditions? 

187.  The  volume  of  gas  in   a  eudiometer  measures 
68  cc.,  the  level  of  the  mercury  in  the  tube  and  trough 
being  the  same.     The  barometer  indicates  an  atmos- 
pheric pressure  of  739  mm.     The  temperature  is  +  20°  C. 
What  would  be  the  volume  of  the  gas  at  0°  C.  and  under 
760  mm.  pressure  ? 

188.  The  volume  of  gas  contained  in  a  tube  measures  76 
cc.     The  mercury  in  the  tube  stands  at  a  height  of  17  mm. 
Barometer  indicates  a  pressure  of  752  mm.     The  tem- 
perature is  +9°  C.     Find  volume  at  0°  C.  and  760  mm. 

189.  If  the  volume  of  a  mass  of  gas  is  500  cc.  at 
-f  30°  C.  and  under  the  pressure  of  100  mm.,  what  would 


CHANGES  IN   VOLUME  45 

it  be  under  the  standard  conditions  of  atmospheric  pres- 
sure and  the  temperature  0°  C.  ? 

190.  If  the  volume  of  a  mass  of  hydrogen  is  1000  cc. 
at  +  100°  C.  and  under  the  pressure  of  800  mm.,  what 
would  it  be  under  standard  conditions  ? 

191.  If  the  volume  of  a  mass  of  oxygen  is  400  cc.  at 
+  50°C.   and   under   the   pressure    of   600mm.,    what 
would  it  be  under  standard  conditions  ? 

192.  If  the  volume  of  a  mass  of  air  is  4 1.  at  +  70°  C. 
and  under  the  pressure  of  80cm.,  what  would  it  be  in 
cc.  under  standard  conditions? 

193.  If  500  cc.  of  chlorine  at  +60°C.  stand  in  a  eu- 
diometer over  mercury,  the  level  within  the  tube  being 
90  mm.  above  that  without  and  the  barometric  pressure 
being  750  mm.,  what  would  be  the  volume  of  the  gas 
under  standard  conditions  ? 

194.  If  1250  cc.  of  nitrogen  at  +  37°  C.   stand  in  a 
eudiometer  over  mercury,  the  level  within  the  tube  being 
20  mm.  below  that  without  and  the  barometric  pressure 
being  747  mm.,  what  would  be  the  volume  of  the  gas 
under  standard  conditions? 

195.  If  780  cc.  of  air  at  +28°  C.  stand  in  a  eudiome- 
ter over  mercury,  the  level  within  the  tube  being  40  mm. 
above  that  without  and  the  barometric  pressure  being 
750mm.,  what  would  be  the  volume  of  the  gas  under 
standard  conditions  ? 

196.  If  J  1.  of  hydrogen  at  +  70°  C.  stands  in  a  eudi- 
ometer over  mercury,  the  level  within  the  tube  being 
50  mm.  below  that  without  and  the  barometric  pres- 
sure being  745  mm.,  what  would  be  the  volume  of  the 
gas  in  cc.  under  standard  conditions  ? 


46       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

197.  If  the  temperature  of  a  certain  volume  of  air  is 
increased  from  —10°  C.  to  -f-30°C.,  how  much  must  the 
pressure  be  increased  to  keep  the  volume  constant  ? 

198.  The  barometer  at  0°  C.  stands  at  750  mm.     At 
what  height  will  it  stand  if  the  temperature  rises  to 
+  39°  C.,  the  pressure  remaining  the  same? 

199.  If  a  quantity  of  gas,  measured  at  0°  C.  and  75  cm. 
pressure,  is  subjected  to  a  pressure  of  775  mm.,  how  much 
must  the  temperature  be  increased  that  the  volume  may 
remain  the  same  ? 

200.  A  sample   of  moist  air,  confined  over  water  at 
+  15°  C.  and  760  mm.,  occupies  15  cc.     It  is  mixed  with 
20  cc.  of  hydrogen,  the  mixture  is  exploded,  and  suffers 
a  contraction  of   9.5  cc.     What  would  be  the  volume 
of  the  oxygen  it  contained  if  measured  dry  at  0°  C.  and 
760  mm.  ? 

201.  To  how  many  atmospheres  pressure  must  a  1. 
of  gas  measured  at   76  cm.  pressure  and  —  20°  C.  be 
subjected  to  be  condensed  to  J  a  1.  when  the  tempera- 
ture is  4-40°  C.? 

202.  A  volume  of  gas  which  measures  2  1.  at  742  mm. 
was  afterwards  found  to  measure  2163  cc.     What  was 
the  height  of  the  barometer  at  the  time  of  the  second 
reading? 

203.  Some    hydrogen  under   900  mm.   pressure  and 
-f  20°  C.  occupies  300  cc.     What  volume  will  it  occupy 
at  +109°  C.  under  600mm.  pressure? 

204.  Find  the  pressure  on  the  gas  in  a  tube  when  the 
mercury  inside  and  outside  the  tube  are  the  same,  and 
the  temperature  is  +25°C.  and  the  barometer  stands 
at  760  mm. 


CHANGES   IN   VOLUME  47 

205.  A  1.  flask  was  filled  with  air  at  —  10°  C.  and 
750mm.  pressure.     If  the  barometer  rises  to  760mm., 
to  what  temperature  must  the  flask  be  raised  to  drive 
out  ^  the  air  that  was  in  it  when  it  was  filled  ? 

206.  The  gas  enclosed  in  a  piston  tube  is  compressed 
to  i|  its  original  volume  measured  at  76  cm.  pressure, 
and  the  temperature  is  raised  from  +10°  C.  to  +130°  C. 
What  is  the  pressure  on  each  cm.2  of  the  piston? 

207.  When  1000  cc.  of  a  gas  were  measured  at  -f  16°  C. 
and  750  mm.,  and  the  volume  was  increased  to  1120  cc. 
by  warming,  the  final  pressure  read  740mm.     What 
was  the  final  temperature  of  the  gas? 

208.  What  decrease  in  temperature  will  be  necessary 
to  reduce  400  cc.  of  a  gas  at  +  20°C.  and  765mm.  to 
a  volume  of  300  cc.  at  750  mm.  ? 

209.  If  1  g.  of  gunpowder  yields,  on  explosion  at  0°  C. 
and  760  mm.,  288  cc.  of  gases,  what  volume  would  be 
occupied  at  +  2200°  C.,  which  is  reached  at  the  moment 
of  exploding? 

210.  What  change  in*  temperature  will  be  necessary 
to  bring  a  volume  of  gas,  measuring  5600  cc.  at  +  10° 
C.  and  745  mm.  pressure,  to  a  volume  of  600  cc.  at  this 
same  pressure? 


CHAPTER   V 

Volumes  of  Gases  from  Weights — Specific  Gravity  and 
Vapor  Density 

1.  Calculate  the  density,  weight  of  11.,  and  sp.  gr. 
of  the  following  gases  : 

C2H2,  CO,  C2H4,  CH4,  C3H8, 

NH3,  COS,  HBr,  NO,  C3H6, 

AsH3,  COC12,  HC1,  N2,  SO2, 

Br2,  C12,  HF,  N2O,  H2O. 

C4H10,  C2N2,  HI,  02, 

CO2,  C2H6,  H2S,  PH3, 

2.  Find  the  weight  of  10  1.  of  NO.     What  volume 
will  5  g.  of  the  gas  occupy  ? 

3.  Find  the  weight  of  the  following  volumes  of  dry 
air  at  standard  conditions  :   (a)  20  cc. ;   (5)  300  cc. ;   (c) 
731.;   (d)30mmA 

4.  Determine  the  weight,  at  0°  C.  and  760  mm.,  of 
1  1.  of  each  of  the  following  gases,  on  the  assumption 
that  they    can   exist  in  the  gaseous  condition  at  the 
standard  temperature  and  pressure  : 

Water,  Trihydrogen  phosphide, 

Hydrogen  chloride,  Alcohol, 

Ammonium  chloride,  Nitrogen  monoxide, 

Carbon  dioxide,  Nitrogen  tetroxide, 

Carbon  disulphide,  Mercuric  chloride. 

48 


VOLUMES,  SPECIFIC  GRAVITY,  VAPOR  DENSITY    49 

5.  What  is  the  weight  of  1500  cc.  of  a  gas  at  the 
standard  pressure  of  760  mm.  and  temperature  of  zero, 
if  its  sp.  gr.  referred  to  hydrogen  is  14? 

6.  Under  a  pressure  of  745  mm.,  1500  cc.  of  chlorine 
weigh  4.67  g.      What   is   the   weight    of  1   1.  under 
standard  pressure  ? 

7.  The  formula  for  ethane  is  C2H6.     Calculate  the 
sp.  gr.  of  its  vapor  (a)  compared  with  hydrogen  ;   (5) 
compared  with  air. 

8.  Two  1.  of  hydrogen  sulphide  weigh  3.0442  g.  ; 
what  is  its  sp.  gr.  referred  to  air  ? 

9.  The  molecular  weight  of  bromine  is  160 ;  what 
is  the  sp.  gr.  ? 

10.  What  will  be  the  volume  of  phosphorus  vapor 
obtained  from  3  g.  of  solid  phosphorus  at  +  420°  C.  ? 

11.  The  density  of  carbon  monoxide  is  14 ;  what  is 
the  weight  of  1  1.  ? 

12.  How  many  1.  of  hydrogen  in  2.7  g.? 

13.  How  many  1.  of  chlorine  in  7.3  g.?     How  many 
cc.? 

14.  What  volume  of  HC1  in  50  g.  ? 

15.  If  2  1.  of  chlorine  weigh  6.3  g.,  find  the  density 
of  chlorine. 

16.  If  5  1.  of  CO2  weigh  9.9  g.,  what  is  its  density? 

17.  If  3  1.  of  mercury  vapor  weigh  26.9  g.,  compute 
the  vapor  density  of  mercury. 

18.  Calculate  the  weight  of  1 1.  of  each  of  the  following 
gases  :  (#)  chlorine ;  (ft)  nitrogen ;  (c)  sulphur  dioxide  ; 
(d)  nitrous  oxide ;   (0)  nitric  oxide ;  (/)  ethane ;   (#) 
butane  ;   Qi)  hydrogen  chloride ;   (i)  carbon  monoxide ; 
(/)  carbon  dioxide  ;  (&)  marsh  gas  ;   (7)  phosphine. 


50       PROGRESSIVE  PROBLEMS  Itf  CHEMISTRY 

19.  What  do  100  1.  of  nitrogen  weigh? 

20.  Nitric  oxide  is  15  times  as  heavy  as  hydrogen ; 
how  many  times  is  it  heavier  than  air  ? 

21.  Calculate  the  density  (referred  to  air)  of  propane. 

22.  Calculate  the  density  (referred  to  air)  of  sulphur 
dioxide. 

23.  The  vapor  of  silicon  chloride  is  5.936  times  as 
heavy  as  air.    Find  its  density  compared  with  hydrogen. 

24.  A  vessel  holding  30.8  g.  of  carbon  dioxide  at 
+  10°C.  and  740  mm.  pressure  is  to  be  brought  to  a 
temperature   of   -f  50°  C.  and  a  pressure  of  750  mm. 
What  weight  and  volume  of  carbon  dioxide  will  be 
lost? 

25.  What  is  the  weight  of  6.594  1.   of   oxygen  at 
+  40°  C.  and  740  mm.  pressure  ? 

26.  The  relative  density  of  carbon  dioxide  is  21.83; 
what  is  the  relative  density  of  this  gas  upon  the  oxygen 
standard  ? 

27.  Find  the  density  (air  =  1)  of  the  following  :    car- 
bon monoxide  ;    carbon  disulphide  ;    sulphur  dioxide  ; 
boron  trifluoride  ;  phosphorus  pentafluoride. 

28.  Find  the  volume  at  standard  conditions  of  1  g. 
H;   16  g.   O;   14  g.  N;   35.5  g.   Cl ;   80  g.   Br  vapor; 
9  g.  steam;  18.25  g.  HC1;  22  g.  CO2;   8  g.  CH4;  32 
g.  S02;  14  g.  CO.  *" 

29.  What  weight  of  arsenic  is  contained  in  a  1.  of 
cacodyl    oxide    vapor,     [(CH3)2As]2O,    measured    at 
+  500°C.? 

30.  What  is  the  volume  of  3.0571  g.  of  a  gas,  if  its 
sp.  gr.  referred  to  air  is  0.591? 


VOLUMES,  SPECIFIC  GRAVITY,  VAPOR  DENSITY    51 

31.  A  hall  is   of  such   dimensions  that  it  contains 
50T.0912  Kg.  of  air  at  0°  C.  and  760  mm.     What  is  the 
capacity  of  the  hall  measured  in  m.3? 

32.  Determine  the  mass  of  750  cc.  of  nitrogen  meas- 
ured over  water  at  +  20°  C.  and  780  mm. 

33.  If  545  cc.  of  nitrogen  are  measured  over  water  at 
+  22°  C.  and  748  mm.  pressure,  what  weight  will  they 
contain  of  the  dry  gas  ? 

34.  What  volume  will  2.2  g.  of  oxygen  at  +20°C. 
and  770  mm.  pressure  occupy  when  transferred  to  a 
vessel  inverted  over  water  ? 

35.  What  volume  will  1  g.  of  hydrogen  measured  at 
standard  conditions  occupy  when  transferred  to  a  vessel 
over  water  at  0°  C.  and  760  mm.  pressure  ? 

36.  What  volume  will  310  g.  of  carbon  dioxide  oc- 
cupy when  contained  in  a  vessel  over  water  at  -f-20°C. 
and  742.4  mm.  pressure  ? 

37.  What  volume  will  1  g.  of  oxygen  occupy  over 
water  at  -f-  30°  C.  and  756.5  mm.  pressure  ? 

38.  At  what  temperature  will  8  g.  of  oxygen  under 
a  pressure  of  760  mm.  occupy  a  volume  of  11.1  1.  at 
this  same  pressure  ? 

39.  Find  the  mass  of  250  1.  of  chlorine  at  -7°C. 
and  886  mm. 

40.  The  sp.  gr.  of  oxygen  under  standard  conditions 
is  1.1;   what  is  the  sp.  gr.  when  the  barometer  stands 
at  745  mm.? 

41.  The  sp.  gr.  of  oxygen  referred  to  hydrogen  is  16 
at  0°C.;    what  is  its  sp.  gr.  when  its  temperature  is 

+  27°C.? 


52       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

42.  If  the  sp.  gr.  of  a  gas  is  22  at  0°  C.,  what  will  be 
itssp.  gr.  at  +  81.9°C.? 

43.  Calculate  the  weight  of  the  following  gases  at 
standard  pressure   and   temperature :    2   1.    of   hydro- 
chloric acid  gas ;  1500  cc.  of  hydrogen  sulphide ;  250 
cc.  of  chlorine ;  5  1.  of  ethane  (C2H6). 

44.  The  density  of  a  substance  referred  to  air  is  3.2. 
What  is  the  density  referred  to  hydrogen  ?     What  will 
be  the  volume  occupied  by  10  g.  of  the  substance  at 
+  20°C.  and  752  mm.? 

45.  How  many  g.  do  10  1.  of  hydrogen  phosphide 
weigh  ? 

46.  A   1.    of   hydrogen   under    standard    conditions 
weighs  0.09  g.     What  is  the  weight  of  a  1.  of  ozone 
under  the  same  conditions? 

47.  A  gas  has  the  formula  C3H8.     Is  it  lighter  or 
heavier  than  air  ?     Find  the  sp.  gr. 

48.  Calculate  the  sp.  gr.  of  cyanogen  and  the  weight 
of  31. 

49.  Determine  the  mass  of  7.3  1.  marsh  gas,  8  1.  of 
ethylene,  and  16  g.  choke  damp,  measured  at  760  mm. 
and  0°  C. 

50.  Find  the  weight  at  +  182°  C.  and  770  mm.  oc- 
cupied by  50  1.  of  (a)  HF,  (5)  HI,  (e)  HC1. 

51.  What  mass  of  nitrogen  will  measure  1000  cc.  at 
+  15°C.  and  765  mm.? 

52.  Find  under  standard  conditions  the  weight  of  1  1. 
of  CO,  CO2,  and  CH4. 

53.  Find  the  mass  of  5.6  1.  of  CO. 

54.  What  space  will  125  g.  of  iodine  vapor  occupy 
at  +  1900°  C.  and  794  mm.  ? 


VOLUMES,  SPECIFIC  GRAVITY,  VAPOR  DENSITY    53 

55.  What  is  the  volume  of  20  g.  of  carbon  dioxide 
at  the  standard  temperature  and  pressure? 

56.  What  is  the  volume  of  82.88  g.  of  the  vapor  of 
ethyl  ether  at  the  temperature  of  + 147°  C.  and  under 
a  pressure  of  740  mm.  ? 

57.  What  weight  of  carbon  does  1  1.  of  CO2  contain ; 
11.  CO? 

58.  What  is  the  weight  of  5  1.  of  ethyl  alcohol  vapor 
having  a  temperature  of  + 127°  C.  and  under  a  pres- 
sure of  750  mm.  ? 

59.  What  is  the  volume  of  a  Kg.  of  carbon  monoxide 
at  0°  C.  and  760  mm.  ? 

60.  What  is  the  volume  of  225  g.  of  hydrogen  sul- 
phide at  0°  C.  and  760  mm.  ? 

61.  Calculate  the  volume,  at  the  standard  tempera- 
ture and  pressure,   of   a  Kg.  of  the  following  gases : 
carbon  monoxide  ;  ethylene  ;  hydrogen  sulphide  ;  oxy- 
sulphide  of  carbon  ;  methyl  hydride  ;  bromine  ;  water. 

62.  What  volume  will  49.63  g.  of  chlorine  occupy  at 
standard  conditions? 

63.  What  is  the  volume  occupied  by  8.8  g.  of  carbon 
dioxide  at  +12°  C.  and  752  mm.  pressure? 

64.  Find  the  volume  of  10  g.  N2O  ;  13  g.  NO ;  7  g. 
N203;  6g.  N204. 

65.  What  volume  of  hydrogen  is  contained  in  6  cc. 
of  NH3? 

66.  Find  the  weight  of  500  cc.  of  H ;  250  cc.  of  Cl; 
700  cc.  of  CH4 ;   130  cc.  of  PH3. 

67.  Find  the  volume  at  +41°  C.  and  785  mm.  oc- 
cupied by  O)  66  g.  CO2;   (6)  96  g.  AsH3. 


54       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

68.  The  weight  of  1  1.  of  aqueous  vapor  at  0°  C.  and 
760  mm.  is  0.8045  g;  what  is  its  relative  density? 

69.  Calculate  the  relative  density  of  mercury  vapor, 
1  1.  of  which  at  standard  conditions  weighs  8.87  g. 

70.  A  1.    of   NH3   weighs    0.762    g.    at    0°   C.    and 
760  mm.      Find  (a)  its  vapor  density  ;   (&)  its  sp.  gr. 

71.  Find  the  volume  at   +41°  C.  and  78.5  mm.  oc- 
cupied by  (a)  66  g.  CO2;   (6)  96  g.  stibine. 

72.  What  is  the  weight  of  573  cc.  of  air  at  +  30°  C. 
and  769  mm.  ? 

73.  What  is  the  weight  of  a  m.3  of  hydrogen  at  the 
standard  temperature  and  twice  the  standard  pressure? 

74.  What   weight  of   hydrogen  and  of   bromine  in 
1  1.  HBr  at  +  60°  C.  and  760  mm.  ? 

75.  How  many  times  heavier  than  a  1.  of  hydrogen  is 
(a)  one  of  air ;   (5)  one  of  oxygen ;  (c)  one  of  chlorine  ; 
(cT)  one  of  nitrogen  ? 

76.  Find  the  weight  of  300  cc.  NH3. 

77.  How  many  g.  in  3000  cc.  of  H2S,  measured  at 
+  16°C.  and  780  mm.? 

78.  Determine    the    mass    of     34   1.    of     (a)    NH3; 
(5)S02;   (OSiF4;   (<OCaHa. 

79.  Find  the  volume  at   -f-  10°  C.  and  761  mm.  oc- 
cupied  by  (a)    3  g.   H2S;    (6)   13   g.   PH3;    (*)  2  g. 
SbH3. 

80.  The  weight  of   2.3  1.   of   oxygen    at  0°  C.  and 
760  mm.    is  3.2885  g.      Find  the  sp.  gr.   referred  to 
air. 

81.  Three  1.  of  marsh  gas  weigh  2.15  g.     What  is 
its  sp.  gr.,  hydrogen  being  the  standard? 


VOLUMES,  SPECIFIC  GRAVITY,  VAPOR  DENSITY    55 

82.  At  760  mm.  pressure,  what  is  the  weight  of  1  1. 
of  acetylene  at  0°  C. ;  of  hydrogen  sulphide  at  0°  C.  ; 
of  steam  at   +150°  C. ;   of  water  at  +4°  C.  ;  of  sul- 
phuric acid,  sp.  gr.  1.84;    of  sulphur  at  -f- 500°  C.;    of 
bromine  at  +  4°  C.  ;  of  bromine  at  -f-  400°  C. ;  of  iodine 
at  +  500°  C. ;  of  iodine  at  +  1500°  C,  ? 

83.  What  volume  is  occupied  by  177.5  g.  of  chlorine? 

84.  Find  the  number  of  1.  occupied  by  64  g.  of  sul- 
phur dioxide ;    occupied  by  32  g.  of  oxygen  ;    occupied 
by  2  g.  of  hydrogen ;  occupied  by  16  g.  of  methane. 


CHAPTER   VI 

Weights  from  Equations 

1.  How  much  KC1O3  must  be  decomposed  to  yield 
20  g.  of  oxygen?     What  weight  of  KC1  will  be  left? 

2.  How  many  g.  of  CO2  will  be  produced  by  burn- 
ing 100  g.  of  carbon  in  oxygen? 

3.  How   many   g.    of  hydrogen    will   result   from 
placing  46  g.  of  sodium  on  water  ? 

4.  How  many  g.  of  acetylene  gas  will  be  generated 
by  750  g.  of  pure  calcium  carbide  ? 

5.  How   many  Ib.  of    water  would   be   needed  to 
slake  15  Ib.  of  CaO? 

6.  In  the  changing  of  500  Ib.  of  Ca(OH)2  in  mortar 
to  CaCO3,  how  many  Ib.   of  water  are  produced  and 
how  many  1.  of  CO2  are  needed? 

7.  How  much  plaster  of  Paris  results  from  heating 
100  Kg.  of  gypsum? 

8.  How  many  Ib.  of  CaO  and  how  many   m.3  of 
CO2  would  be  formed  by  heating  5  tons  of  limestone? 

9.  From  30  tons  of  sodium  nitrate,  how  much  nitric 
acid  (80%    HNO3)  can  be  produced?     How  much  sul- 
phuric acid  is  necessary  to  make  it  ? 

10.    How  much    CO    will    result   on  heating  70  g. 
of  H2C2O4  with  concentrated  H2SO4? 

56 


WEIGHTS  FROM   EQUATIONS  57 

11.  If  100  g.  H2C2O4  are  heated  with  H2SO4  and  the 
gases  are  passed  through  a  solution  of  NaOH,  what 
volume  of  CO  and  what  weight  of  Na2CO3  will  result  ? 

12.  What  weight  of  HC1  cau  be  made  from  50  g.  of 
NaCl? 

13.  What  weight  of  arsenic  would  be  obtained    by 
reducing  157  g.  of  arsenic  trioxide  with  charcoal  ? 

14.  If  a  candle  consists  of  85  %  of  carbon  and  15  %  of 
hydrogen,  what  weights  of  carbon  dioxide  and  water 
will  be  formed  when  25  g.  of  the  candle  burn  ? 

15.  To  what   weight   of  nitrous  acid  do  100  g.  of 
nitrous  anhydride  correspond  ? 

16.  How  much  nitrogen  peroxide  is  obtainable  from 
200  g.  of  nitric  acid? 

17.  What  weight  of  copper  nitrate  is  obtainable  from 
50  g.  of  nitric  acid  and  copper? 

18.  How  much  nitrogen  peroxide  can  be  made  from 
100  g.  of  nitric  oxide  ? 

19.  How  much  hydrocyanic  acid  is  obtainable  from 
70  g.  of  potassium  cyanide  ? 

20.  How  much  cyanogen  is  obtainable  from  200  g.  -of 
mercuric  cyanide  ? 

21.  What  weight  of  carbon  dioxide  will   300  g.   of 
calcium  carbonate  yield  on  treatment  with  an  acid? 

22.  What  weight  of  NaOH  and  HC1  will  be  needed 
to  produce  75  g.  of  NaCl? 

23.  If  100  Kg.  of  "fool's  gold"  are  heated  (a)  in 
a  tube,  (5)  in  the  air,  what  are  the  weights  of  the  sub- 
stances produced  in  each  case  ? 

24.  What  weight  of  Na2CO3  will  result  from  heating 
500  g.  of  sodium  dicarbonate  ? 


58       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

25.  What  weight  of  washing  soda  would  be  needed 
to  furnish  125  g.  of  anhydrous  Na2CO3? 

26.  What  weight  of  nitric  acid  will  be  produced  by 
heating  75  g.  of  Chili  saltpeter  with  an  excess  of  con- 
centrated sulphuric  acid  ? 

27.  What  weight  of  sulphuric  acid  and  sodium  ni- 
trate should  be  taken  in  order  to  obtain  215  g.  of  nitric 
acid? 

28.  If  78  g.  of  copper  nitrate  is  decomposed  by  con- 
centrated sulphuric  acid,  what  weight  of  nitric  acid  and 
what  weight  of  copper  sulphate  will  be  formed? 

29.  If  copper  and  nitric  acid  react,  what  weight  of 
metallic  copper  should  be  taken,  if  one  Kg.  of  copper 
nitrate  is  to  be  formed? 

30.  What  weight  of  nitrogen  tetroxide  (N2O4)  will 
result  when  3300  cc.  of  nitric  oxide  (NO)  is  brought  into 
contact  with  an  excess  of  oxygen  ? 

31.  What  weight  of  N2O  will  be  formed  by  heating 
50  g.   of  NH4NO3?     How  many  g.   of  water  will  be 
formed? 

32.  What  weight  of  NH4NO3  will  be  taken  to  yield 
upon  heating  1  1.  of  N2O  ? 

33.  What  weight  of  NH3  will  result  upon  decompos- 
ing 50  g.  of  NH4C1  with  slaked  lime? 

34.  What  weight  of  potassium  and  what  weight  of 
chlorine  are  contained  in  17  g.  of  potassium  chlorate? 

35.  How  much  potassium  chloride  would  be  formed 
by  heating  35  g.  of  potassium  chlorate  ? 

36.  How  much  BaO2  must  be  heated  in  order  to  ob- 
tain 14  g.  of  oxygen? 


WEIGHTS  FROM  EQUATIONS  59 

37.  If  potassium  chlorate  costs  80  cts.  per  Kg.,  what 
will  be  the  cost  of  enough  to  make  500  g.  of  oxygen  ? 

38.  What  weight  of  sodium  will  be  necessary  to  de- 
compose 15  g.  of  water?     What  weight  of  hydrogen 
will  be  formed  ? 

39.  What  weight  of  sodium  would  be  needed  to  pro- 
duce, by   the  decomposition  of   water,   1  1.    of  hydro- 
gen? 

40.  What  weight  of  oxygen  can  be  obtained  by  heat- 
ing 18  g.  of  mercuric  oxide  ? 

41.  How  much  mercuric  oxide  must  be  heated  in 
order  to  obtain  2  g.  of  oxygen? 

42.  With  what  weight  of  mercury  will  9  g.  of  oxy- 
gen unite  to  form  mercuric  oxide? 

43.  To  obtain  15  g.  of  iodine,  how  much  manganese 
dioxide,  potassium  iodide,  and  sulphuric  acid  will  be  re- 
quired? 

44.  What    weight    of    hydrofluoric   acid    would   be 
evolved  by  treating  36  g.  of  calcium  fluoride  with  sul- 
phuric acid? 

45.  How  much  common  salt  will  be  needed  to  yield 
10  g.  of  chlorine  on  treatment  with  manganese  dioxide 
and  sulphuric  acid? 

46.  What  weight  of  zinc  sulphate  will  be  formed  upon 
treating  13  g.  of  zinc  with  sulphuric  acid? 

47.  How  much  manganese  dioxide  will  be  required 
to  liberate  13  g.  of  chlorine  from  hydrochloric  acid? 

48.  What  weight  of  chlorine  will  result  from  the 
electrolysis  of  a  solution  containing  65  g.  of  potassium 
chloride  ? 


60       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

49.  An  ore  contains  62.38%  of  arsenopyrite  (FeAsS). 
What  weight  of  white  arsenic  could  be  obtained  by 
heating  500  Ib.  of  the  ore  ? 

50.  What  weights  of  mercury  and  sulphur  dioxide 
could  be  obtained  from  1  ton  of  an  ore  carrying  53.78% 
of  cinnabar? 

51.  What  weight  of  aluminum  oxide  is  contained  in 
100  Ib.  of  potassium  alum? 

52.  What  weight  of  aluminum  hydroxide  will  be  pro- 
duced when  a  solution  containing  35  g.  of  potassium  alum 
is  precipitated  with  ammonium  hydroxide? 

53.  An  ore  contains  23.46  %  of  stibnite,  Sb2S3  ;  what 
is  the  °/0  of  antimony  in  the  ore  ? 

54.  How  many  Ib.  of  calcium  carbide  will  be  neces- 
sary to  produce  1300  g.  of  acetylene? 

55.  How  many  Ib.  of  zinc  may  be  obtained  from  a 
ton  of  an  ore  containing  17.3  %  of  zinc  carbonate? 

56.  What  weight  of  silicon  tetrafluoride  could  be  ob- 
tained by  treating  430  g.  of  silica   with   hydrofluoric 
acid? 

57.  If  275  g.  of  silica  is  fused  with  an  excess  of  po- 
tassium carbonate,  what  weight  of  potassium   silicate 
(K2SiO3)  will  result? 

58.  From  1500  Ib.  of  salt  how  many  Kg.  of  sodium 
carbonate  can  be  obtained  by  the  Leblanc  process  ?    How 
much   charcoal  and  how  much  limestone  will  be  re- 
quired ? 

59.  What  weight  of  calcium  sulphide  will  be  pro- 
duced in  the  manufacture  of  1  ton  of  dry  sodium  car- 
bonate by  the  Leblanc  process? 


WEIGHTS  FROM   EQUATIONS  61 

60.  What  weights  of  salt,  ammonia,  and  carbon  dioxide 
will  be  necessary  to  produce  1  ton  of  NaHCO3  by  the 
Solvay  process? 

61.  In  a  case  of  poisoning,  11.73  g.  of  arsenic  tri- 
sulphide  were  found ;  to  how  much  arsenic  trioxide  does 
this  correspond? 

As2S3  +  9  O  =  As2O3  +  3  SO2. 

62.  If  I  wish  to  make  ferrous  sulphide,  how  many  g. 
of  sulphur  should  I  mix  with  56  g.  of  iron  filings,  and 
how  much  ferrous  sulphide  should  result  ? 

63.  How  much  hydrogen  and  how  much  zinc  chloride 
should  result  from  treating  25  g.  of  zinc  with  a  sufficient 
quantity  of  hydrogen  chloride  ? 

64.  What  weight  of  oxygen  is  needed  to  burn  a  dia- 
mond which  weighs  half  a  gr.  ?     What  will  the  CO2 
formed  weigh  ? 

65.  How  much  sulphuric  acid  will  neutralize  50  Ib. 
of  sodium  hydroxide  ? 

66.  How  much  lead  is  needed  to  form  2  Kg.  of  lead 
nitrate  ? 

67.  How  many  g.  of  HNO3  will  140  g.  of  NH4NO3 
give  ? 

68.  How  many  g.  of  iodine  in  166  g.  of  KI  ? 

69.  How   many    tons    of    pyrite    containing    39.2% 
of  available  sulphur  are  needed  to  make  4000  tons  of 
sulphuric  acid  of  sp.  gr.   1.730  containing  80%  pure 
H2SO4  and  allowing  for  no  losses  ? 

70.  What  weight  of  iron  rust  may  be  obtained  with 
a  supply  of  10  g.  of  oxygen  ? 

71.  How  much  MnO2  is  needed  to  make  125  g.  of 
chlorine  from  HC1  ? 


62       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

72.  What  weight  of  ammonium  chloride,  when  acted 
upon  by  calcium  hydroxide,  is  required  to  produce  17 
g.  of  ammonia,  and  what  weight  of  calcium  chloride  is 
formed  at  the  same  time  ? 

73.  How  much  "  laughing  gas  "  may  be  made  from 
80  g.  of  NH4N03? 

74.  How  much  KI  is  needed  to  prepare  63.5  g.  of 
iodine  ? 

75.  How  much  K2CO3  and  Ca(OH)2  will  give  a  Kg. 
of  KOH  ? 

76.  Find  the  weight  of  Hg  and  O  from  decomposing 
10  g.  of  HgO. 

77.  How  many  g.  of  NH4NO3  must  be  used  to  pro- 
duce 20  g.  of  N2O  ? 

78.  How  much  phosphorus  is  there  in  1  ton  (2000 
Ib.)  of  bone  ash? 

79.  What  weight  of  zinc  will  be  required  to  decom- 
pose 10,000  Ib.  of  sulphuric  acid  ? 

80.  What  weight  of  zinc  and  of  sulphuric  acid  is 
necessary  to  prepare  50,000  1.  of  hydrogen  at  +  31°  C. 
and  758  mm.  pressure  ? 

81.  One  Kg.  of  phosphorus  is  converted  into  phos- 
phoric  anhydride.     What  weight  of   phosphoric  acid 
will  this  yield  ? 

82.  Find  the  g.  of  each  component  in  76  g.  of  HNO3. 
How  many  g.  of  nitric  oxide  can  be  set  free  by  the 
action  of  252  g.  of  HNO8  on  copper  ? 

83.  What  weight  of  sulphur  is  contained  in  100  g.  of 
pyrite  ? 

84.  How  much  silver  is  contained  in  100  g.  of  an 
impure  specimen  of  silver  chloride  which  is  33  %  sand  ? 


WEIGHTS  FROM   EQUATIONS  63 

85.  What  weight   of  oil  of  vitriol   of   97  %   can   be 
made  from  1000  Kg.  of  sulphur  ? 

86.  What  weight  of  oxygen  is  necessary  to  burn  the 
sulphur   derived   from   the   decomposition   of   1   g.    of 
sulphurous  anhydride,  and  what  is  the  weight  of  the 
product  ? 

87.  Calculate  the  weight  of  tin  and  hydrochloric  acid 
necessary  to  produce  16  g.  of  hydrogen. 

88.  How  much   sodium   carbonate  and  calcium  hy- 
droxide are  needed  to  make  a  Kg.  of  sodium  hydroxide  ? 

89.  Find  the  weight  of  each  of  the  products  formed 
by  the  complete  combustion  of  52  g.  of  turpentine. 

90.  A  certain  weight  of  MnO2  is  heated  till  decom- 
posed;   if  the  residue  weighs  149  g.,  what  weight  of 
oxygen  was  evolved  ? 

91.  How  many  g.  of  CaCO3  must  be  used  to  prepare 
22  g.  of  carbon  dioxide  by  the  action  of  HC1  ? 

92.  If   2  g.    of  silver   are  dissolved   in  nitric   acid 
and  half  a  g.  of  pure,  dry  sodium  chloride  is  added, 
what  percentage  of  the  silver  remains  in  solution  ? 

93.  How  much  potassium,  by  its  action  upon  water, 
is  required  to  furnish  2J  g.  of  hydrogen  ? 

94.  Find  the  number  of  g.  of  HC1  that  can  be  set 
free   by   the    complete   action   of   10  g.   of  H2SO4  on 
common  salt. 

95.  The  ammonia  obtained  from  20  Kg.  of  ammo- 
nium chloride  is  united  with  sulphuric  acid  to  form  the 
neutral  salt.     What  is  the  weight  of  the  product  ? 

96.  How  many  Ib.  of  limestone  are  needed  to  pro- 
duce 1  ton  of  quicklime  ? 


64       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

97.  To  obtain  15  g.  of  bromine,  how  much  MnO2, 
KBr,  and  H2SO4  should  be  used  ? 

98.  What  weight  of  a  gas  mixture  known  as  "  water 
gas"  can  be  obtained  from  24  Ib.  of  carbon  and  the 
necessary  steam  ? 

99.  What  is  the  weight  of  BaO  in  1.5  g.  of  barium 
carbonate? 

100.  How  many  g.  of  silver  will  5  g.  of  sodium  bro- 
mide precipitate  from  a  solution  of  silver  in  nitric  acid  ? 

101.  If  a  solution  containing  50  g.  of  lead  nitrate 
is  precipitated  by  hydrogen  sulphide,  what  will  be  the 
weight  of  the  precipitate  ? 

102.  If  a  solution  containing  50  g.  of  copper  sulphate 
is  precipitated  by  hydrogen  sulphide,  what  will  be  the 
weight  of  the  precipitate  ? 

103.  How  much    sulphuric  acid  could  be  produced 
from  the  sulphur  dioxide  arising  from  the  combustion 
of  1  ton  of  sulphur?  . 

104.  How   much   sulphuric  acid  could  be  produced 
from  the  sulphur  dioxide  arising  from  the  combustion 
of  1  ton  of  pure  pyrite  ? 

105.  If  100  cc.  of  a  solution  of  barium  chloride  that 
contains  20  g.  of  the  salt  in  1  1.  is  precipitated  by  sul- 
phuric acid,  what  weight  of  BaSO4  will  be  formed  ? 

106.  How   much   potassium  chlorate    can   be    made 
from  150  g.  of  potassium  hydroxide  according  to  the 
following  reaction  : 

6  KOH  +  3  C12  =  KC1O3  +  5  KC1  +  3  H2O  ? 

107.  How  much  AgNO3  can  be  obtained  from  15  g. 
of  Ag,  and  how  much  H2O  and  how  many  g.  of  NO 
will  be  formed  ? 


WEIGHTS  FROM   EQUATIONS  65 

108.  AsH3  is  decomposed  into  its   elements.     How 
many  mg.  of  each  element  from  550  cc.  of  AsH3  ? 

109.  How   much   hydrogen   potassium   carbonate   is 
required  to  give  1.98  g.  of  carbon  dioxide  ? 

110.  How  much  manganese  dioxide  is  required  to 
charge  a  wedge-shaped  gas  bag,  1  m.  high  and  wide 
and  |  m.  basal  thickness,  with  oxygen  at  +15°  C.? 

111.  One  g.  of  Ca(OCl)2  is  boiled  with  water  and 
CuO.     What  weight  of  oxygen  is  evolved  ? 

112.  A  solution  contains  30  g.  of  silver  nitrate.     How 
much  common  salt  is  required  to  decompose  the  silver 
nitrate,  and  how  much  silver  chloride  is  produced  ? 

113.  If  1  Kg.  of  HNO3  is  needed,  what  weights  of 
materials  are  required  to  make  it  ? 

114.  CHKO2  (potassium  formate)  +  KOH  =  K2CO3 
+  H2.     In  the  above  equation,  if  1  Kg.  of  CHKO2  is 
used,  find  the  weight  of  gas  evolved. 

115.  How  much  hydrochloric  acid  can  be  obtained  by 
treating  1  Kg.  of  common  salt  with   sulphuric  acid? 
How  much  sulphuric  acid  will  be  needed  ? 

116.  A  piece  of  potassium  is  thrown  on  water;  the 
KOH    will    just    neutralize    50    cc.    of    a   solution   of 
H2SO4  containing  98  g.     Find  the  weight  of  potassium 
used. 

117.  If  2  g.  of  Ag2O  are  thrown  into  hydrogen  perox- 
ide, what  weight  of  gas  is  evolved  ? 

118.  If  200  Ib.  of  nitre  and  enough  H2SO4  are  heated 
together,  what  weight  of  HNO3  is  given  off? 

119.  What    weight    of    CO2   is   needed   to   convert 
50    tons    of    "soda"     crystals    into    dicarbonate    of 
soda? 


66        PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

120.  A  diamond  weighing  0.3  g.  is  burned  in  a  jar 
of  oxygen.     How  much    CaCO3  would  be  formed  by 
shaking  the  contents  of  flask  after  combustion  with  lime- 
water  ? 

121.  A  certain  amount  of  H2SO4  requires  10  g.  of 
BaCl2  to  precipitate  it  completely.     Find  the  weight  of 
acid  used. 

122.  How  much  water  must  be  added  to  100  g.  of 
P2O6  to  form  orthophosphoric  acid  ? 

123.  A   copper   coin   liberates   from   sulphuric   acid 
22  g.  of  SO2.     Find  the  weight  of  the  coin. 

124.  How  much  carbon  heated  in  the  air  will  give 
14  g.  of  C02? 

125.  13  g.  C6H6  is  burned  in  air.     Find  the  weight  of 
oxygen  used  and  the  weight  of  the  gaseous  products. 

126.  What  weight  of  calcium  carbide  (3  C  +  CaO  = 
CaC2  +  CO)  will  600  Ib.  of  lime  make  ?     How  much 
carbon  is  needed  ? 

127.  Hydrogen  is  passed  over  2.48  g.  of  heated  CuO 
and  the  weight  is  2.24  g.     The  water  formed  weighs 
0.27  g.     Calculate  the  weight  of  H  and  O. 

128.  How  much  KC1  can  be  obtained  from  200  g. 
KC1O3  containing  12%  of  impurities?     Find  weight  of 
oxygen  given  off. 

129.  Iron  dissolved  in  hydrochloric  acid  gives  66  cc. 
of  hydrogen.     Find  the  weight  of  iron  used. 

130.  Water  is  decomposed  and  the  oxygen  is  burned 
with  pure  carbon,  giving  44  g.  of  CO2.     How   much 
water  was  used? 

131.  One  Kg.  of  NaNO3  is  treated  with  oil  of  vitriol. 
Find  the  weight  of  aqua  fortis  produced. 


WEIGHTS  FROM   EQUATIONS  67 

132.  How  much  fluorspar  will  be  needed  to  unite 
with  100  g.  of  H2SO4? 

133.  If  10  g.  of  carbon  are  heated  with  67  g.  of  CO2, 
what  weight  (a)  of  CO  is  formed;   (6)  of  residue,  if 
any? 

134.  vTo   get    76   Kg.    of   oxygen,  how  much  air   is 
needed? 

135.  In  300  Ib.  of  bone  ash  are  contained :   (a)  how 
many  Ib.  of  oxygen ;  (&)  how  much  calcium  ? 

136.  If  the  bones  of  a  man  weigh  26  Ib.  and  contain 
60  %    Ca3(PO4)2,  find  (a)  the  weight  of  phosphorus; 
(5)  the  value  of  the  skeleton  to  make  phosphorus  pent- 
oxide  at  |3  a  pound. 

137.  If   4    Kg.  of   Na2CO3  are  heated  with  carbon, 
what  is  the  weight  of  sodium  produced  and  of  carbon 
used? 

138.  How  many  g.  of  oxygen  and  of  hydrogen  can 
be  obtained  by  the  decomposition  of  27  g.  of  water? 

139.  How  many  g.  of  oxygen  can  be  obtained  by  the 
decomposition  of  100  g.  of  mercuric  oxide? 

140.  If  3  g.  of  urea  are  warmed  with  KNO3  and  hy- 
drogen sulphate,  what  weights  of  gases  are  given  off? 
CON2H4  +  O3  =  N2  +  2  H2O  +  CO3. 

141.  Calculate  the  weight  of  iron  that  would  be  dis- 
solved by  100  g.  of  a  solution  of  hydrochloric  acid  con- 
taining 20  %  by  weight  of  the  gas. 

142.  Calculate  the  weight  of  zinc  sulphate  that  would 
be  produced  by  dissolving  10  g.  of   zinc  in  sulphuric 
acid. 

143.  How  much  iodine  can  be  obtained  from  236  g. 
of  potassium  iodide  ? 


68       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

144.  What  weights  of   iron,  iodine,  and  K2CO3  are 
needed  to  make  347  g.  of  KI  ? 

145.  What    is    the    weight   of    potassium    chlorate 
yielded  by  the  chlorine  evolved  from  100  tons  of  man- 
ganese ore  containing  60  %  of  the  dioxide? 

146.  What    weight    of    potassium    bromate   can    be 
obtained  by  neutralizing  520  g.  of  bromine  with  pot- 
ash? 

147.  A  manufacturer  of  bleaching  powder  requires 
10  tons  of  chlorine.     How  much  salt,  manganese  ore 
containing  59  %  of  the  dioxide,  and  sulphuric  acid  con- 
taining 58  %  of  real  acid  will  he  need? 

148.  What  weight  of  MnO2,  when  heated,  will  yield 
1  g.  of  oxygen? 

149.  If  2000  g.  Cu  are  heated  in  air,  what  weight  of 
oxygen  will  be  used  and  what  weight  of  CuO  will  be 
produced  ? 

150.  I  require  2  Kg.  of  oxygen ;  how  much  (a)  mer- 
curic oxide,  (5)  potassium  chlorate,  and  (<?)  manganese 
dioxide,  and  (c?)  sulphuric  acid  shall  I  need? 

151.  How  much  KMnO4  is  needed  to  furnish  1  Ib.  of 
oxygen  ? 

152.  If  132.74  Kg.  of  hydrogen  are  needed  to  inflate 
a  balloon,  what  weight  of  zinc  and  sulphuric  acid  will 
be  required  to  produce  this  quantity  of  gas  ? 

153.  Since  77  %  of  the  weight  of  the  air,  freed  from 
moisture  and  CO2,  consists  of  nitrogen,  calculate  the 
weight  of  (a)  metallic  copper,  and  (5)  of  phosphorus 
required  to  abstract  the  oxygen  from  1  Ib.  of  air. 

154.  In  burning  17  g.  of  alcohol,  find  the  weight  of 
the  products. 


WEIGHTS  FROM   EQUATIONS  69 

155.  How  much  NH4NO3  would  produce  enough  N2O 
for  the  combustion  of  36  g.  of  carbon  ? 

156.  How  much  nitrogen  can  be   produced  by  the 
combustion  of  NH3  produced  by  the  action  of  15  g.  of 
NH4C1  on  NaOH  ? 

157.  How  much  K2Cr2O7  will  be  needed  to  convert 
10  g.  of  FeCl2  to  FeCl3  ? 

158.  How  many  g.    of  acetic  acid  are  required  to 
neutralize  6  g.  of  K2CO3? 

159.  If  a  solution  contains  30  g.  KI,  how  much  chlo- 
rine would  be  needed  to  liberate  all  the  iodine,  and  how 
much  KC1  would  result  ? 

160.  What  weight  of  SnCl2  is  needed  to  precipitate 
completely  the  gold  in  200  g.  of  AuCl3  ? 

161.  If  100  g.  MnO2  are  treated  with  HC1  in  excess, 
what  weight  of  chlorine  is  evolved  ?     If  treated  with 
enough  NaCl  and  H2SO4,  how  much  chloride  would  be 
necessary  ? 

162.  If  300  g.  of  cinnabar  are  heated,  (#)  how  much 
oxygen  is  needed  ;   (6)  what  weight  of  mercury  is  left  ? 

163.  If  63  g.  of  lead  are  heated,  how  many  g.  of  PbO 
are  produced  ? 

164.  If  100  g.  of  copper  and  100  g.  of  sulphur  are 
heated  together,  what  substances  will  be  found  after 
combination  and  how  much  of  each  ? 

165.  If  32  g.  Cu,  103  g.  Pb,  12  g.  Mg,  and  25  g.  Fe 
are  each  heated  in  the  air  till  they  cease  to  gain  in 
weight,  how  many  g.  will  each  gain  ? 

166.  How  much  iron  is  needed  to  throw  down  all  the 
copper  in  a  CuSO4  solution  containing  160  g.  and  what 
weight  of  FeSO4  will  be  formed  ? 


70       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

167.  Calculate  the  weight  of  air  required  to  burn  a 
ton  of  coal   possessing  the  following  percentage  com- 
position :     carbon,    88.42 ;    hydrogen,    5.61  ;    oxygen, 
5.97. 

168.  What  weight  of  potassium  chlorate  is  needed  to 
furnish  oxygen  sufficient  to  burn  the  hydrogen  evolved 
by  the  action  of  water  on  200  g.  of  calcium  ? 

169.  If  100  g.  of  pure  iron  are  burnt  in  excess  of  (a) 
oxygen  and  (6)  chlorine,  what  is  the  weight  of  oxide 
and  chloride  produced  ? 

170.  How  much  nitre  and  sulphuric  acid  shall  I  need 
to  prepare  nitric  acid  enough  to  neutralize  exactly  5  Ib. 
of  chalk  ? 

171.  How  much  pure  zinc  will  be  required  to  prepare 
1  Kg.  of  hydrogen  ? 

172.  What  weights  of  NaOH  and  H2SO4  are  needed 
to  produce  100  g.  of  Na2SO4? 

173.  How  many  g.  of  sulphuric  acid  and  of  nitre  are 
required  to  make  250  g.  of  nitric  acid  ? 

174.  How  much  crystallized  microcosmic  salt  must  be 
ignited  to  furnish  a  g.  of  sodium  metaphosphate? 

175.  What  weights  of  copper  and  sulphuric  acid  are 
needed  to  yield  30  g.  of  sulphurous  acid  at  the  stand- 
ard temperature  and  pressure? 

176.  What  weight  of  iron  is  contained  in  10  tons  of 
pyrite? 

177.  What  weight  of  silver  chloride  will  be  formed  by 
the  reaction  of  0.2008  g.  of  sodium  chloride  with  silver 
nitrate  in  solution? 

178.  How  many  tons    of   coke    containing   97  %   of 
carbon  are  required  to  reduce  388  tons  of  hematite  ? 


WEIGHTS  FROM   EQUATIONS  71 

179.  How  much  carbon  would  be  necessary  to  reduce 
9  g.  of  copper  oxide  ? 

180.  How   much    sulphuric   acid  (80%)   should   be 
procurable  from  5  tons  of  pyrite  which  carries  44  %  of 
sulphur? 

181.  Suppose  a  glass  had  the  formula  Na2O,  CaO, 
6  SiO2,  how  much  sodium  carbonate  and  limestone  would 
be  necessary  to  make  250  Ib.  ? 

182.  If  monazite   sand  contains  4  %  of  ThO2,  how 
many  tons  of  the  sand  would  be  necessary  to  produce 
24,000,000  mantles,  if  each  mantle  weighs  6  g.  ? 

183.  How  many  Ib.  of  pig  iron  containing  95%  Fe 
can  be  made  from  2000  Ib.  Fe2O3? 

184.  How  much  copper  oxide  would  be  used  and  cop- 
per obtained  in  preparing  3.2  g.  of  water? 

185.  How  much  carbon  dioxide  and  disulphide,  re- 
spectively, can  be  produced  from  4  Ib.  of  pure  char- 
coal? 

186.  How  much  barium  dioxide  is  necessary  to  make 
5  Ib.  of  a*  4  %  solution  of  hydrogen  dioxide  ? 

187.  How  much  lime  is  theoretically  obtainable  from 
9  tons  of  limestone  which  is  97  %  pure? 

188.  What  weight  of  sodium  chloride,  when  treated 
with  sulphuric  acid,  will  produce  100  g.  of  sodium  sul- 
phate ? 

189.  What  weight  of  sulphuric  acid  can  be  manufac- 
tured from  a  ton  of  pyrite  ? 

190.  What  mass  of  water  will  be  needed  to  convert 
142   g.    of    P2O5    into   (a)  hydrogen   orthophosphate ; 
(5)  hydrogen  pyrophosphate ;  (<?)  hydrogen  metaphos- 
phate  ? 


72       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

191.  What  weight  of  KMnO4  will  be  needed  to  con- 
vert 139  g.  of  FeSO4,  7  H2O  into  the  ferric  condition  ? 

192.  We  need  4711  g.  common  alum ;  what  weight 
of  "alumina"  is  needed? 

193.  How  much  of  each  material  would  be  needed  to 
produce  502  g.  of  "manganese  alum"? 

194.  How  much  water  is  necessary  to  convert  55  g.  of 
P2O3  into  hydrogen  phosphite? 

195.  What  mass  of  oxygen  can  be  obtaine.d  by  heat- 
ing («)  24  g.  KC1O3;  (5)  174  g.  MnO2 ;  (c)  49  g.  KC1O3 
and  MnO2;  (d)  100  g.  HgO  ;  (e)  200  g.  Cu(NO3)2? 

196.  How  many  g.  of  commercial  HNO3  (containing 
68%  HNO3)  will  be  needed  to  decompose  (a)  100  g. 
marble  ;  (6)  100  g.  Na2GO3  ? 

197.  What  weight  of  hydrogen  can  be  obtained  by 
the  action  of  112  g.  KOH  on  potassium  formate? 

-  198.    Find  weight  of  oxygen  needed  to  burn  150  g. 

of  CS2. 

199.  How  many  g.  arsenic  are  needed  to  make  200  g. 
of  arsenibus  oxide  ? 

200.  What  weight  of  magnesium  oxide  will  be  pro- 
duced by  burning  0.5  g.  of  magnesium  ribbon? 

201.  What   weight  of   oxygen  will   be  obtained  by 
heating  26  g.  of  potassium  chlorate  ? 

202.  What  weight  of  quicklime  can  be  obtained  from 
1800  Ib.  of  limestone  ? 

203.  How   much   carbon   dioxide   may  be    obtained 
from  22  g.  calcium  carbonate? 

204.  Ten  g.   of  sodium  hydroxide  are  dissolved    in 
water,  a  volume  of  hydrochloric  acid  containing  15  g. 


WEIGHTS  FROM   EQUATIONS  73 

of  hydrogen  chloride  is  added,  and  the  mixture  is 
evaporated  to  dryness.  Of  what  does  the  residue  con- 
sist and  what  is  the  weight  of  each  constituent  ? 

205.  What  weight  of  silver  nitrate  could  be  obtained 
by  dissolving  a  ten-cent  piece,  weighing  2.44  g.  and 
containing  90  %  silver,  in  dilute  nitric  acid  and  evapo- 
rating ? 

206.  Assume    that   "thermit"    contains   75%    iron 
oxide ;  how  much  of  the  mixture  would  be  required  to 
produce  6  Ib.  of  metallic  iron? 

207.  How  many  pailf  uls  of  water,  12  Kg.  each,  would 
be  required  to  slake  250  Ib.  of  quicklime  ? 

208.  How  many  Ib.  of  pure  calcium  cyanamide  would 
be  required  to  produce  40  Ib.  of  ammonia? 

209.  If  80  g.  of  potassium  chlorate  are  decomposed, 
the  oxygen  collected,  and  magnesium  is  burned  in  the 
oxygen  until  no  gas  remains,  what  weight  of  magnesium 
is  required  ? 

210.  What  weight  of  sodium  carbonate  can  be  made 
from  500  Kg.  of  common  salt? 

211.  How  much    nitrogen    tetroxide   may  be  made 
according  to  theory  from  8  g.  of  lead  nitrate? 

212.  How  much  iron  could  be  obtained  from  40  g.  of 
Fe2O3,  and  what  weight  of  hydrogen  would  be  required 
to  effect  this  process? 

213.  How  much  AgCl  will  be  formed  by  the  addition 
of  10  g.  of  barium  chloride  to  an  excess  of  AgNO3? 

214.  How  much  red  lead  could  be  made  from  800  Kg. 

of  litharge  ? 

215.  What  weight  of  A12O3  will  be  needed  to  prepare 
94.8  g.  of  potash  alum? 


74       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

216.  How  much  CaSO4  can  be  formed  from  37  g.  of 
CaCl2  ? 

217.  Calculate  the  amount  of  Ba(NO3)2  necessary  to 
precipitate  120  g.  of  dilute  H2SO4  containing  50  %  of 
water. 

218.  How  many  Ib.    of   Ag2O    are  needed  to  make 
3100  Ib.  of  oxygen  ? 

219.  How  much  K2CO3  is  needed  to  precipitate  com- 
pletely 109.5  g.  of  CaCl2? 

220.  What  weight  of  phosphorus  is  needed  to  pro- 
duce 100  g.  of  Mg2P2O7? 

221.  What   weight   of   zinc,   sodi-um,   calcium,  iron, 
and  magnesium  will  be  required  to  produce  10  g.  of 
hydrogen  ? 

222.  How  many  g.  of  CO2  will  combine  with  100  g. 
of  CaO  to  form  CaCO3? 

223.  If  560  g.  of   bromine   are  treated  with  KOH, 
what  weight  of  potassium  bromate  is  produced? 

224.  If  6  g.  of  carbon  and  22  g.  of  oxygen  are  heated 
in  a  closed  tube,  what  is  the  weight  of  the  resulting 
substances  ? 

225.  If  294  g.    K2Cr2O7  are  wanted,  what  weight  of 
K2CrO4  will  be  used? 

226.  If  5.75  g.  of  silver  nitrate  are  added  to  5.75  g. 
of  a  solution  of  hydrochloric  acid  containing  10.22% 
HC1,  how  much  silver  is  precipitated  and  how  much 
remains  in  solution? 

227.  What  weight  of  oxygen  is  needed  to  burn  15  g. 
of  charcoal  (90  %  C  and  4%  H)? 

228.  What  weight  of  CO2  is  needed  to  convert  90 
tons  of  soda  crystals  into  bicarbonate  ? 


WEIGHTS   FROM   EQUATIONS  75 

229.  What  weight  of  chlorine  could  be  obtained  by 
acting  upon  20  g.  of  pure  manganese  dioxide  with  hy- 
drochloric acid? 

230.  What  weight  of  oxygen  could  be  obtained  by 
the  complete  decomposition  of  100  g.  of  pure  potassium 
chlorate  ?     If  the  chlorate  used  contained  10  %  of  its 
weight  of  potassium  chloride,  what  would  be  the  differ- 
ence in  the  amount  of  oxygen  Obtained? 

231.  A  solution  of  nitric  acid  of  sp.  gr.  1.46  contains 
80  %  of  HNO3.     What  weight  of  this  solution  is  theo- 
retically required  to  dissolve  10  g.  of  copper  oxide? 

232.  How  much  BaO2  would  yield  as  much  oxygen 
as  250  g.  of  mercuric  oxide? 

233.  When  0.542  g.  of  a  salt  of  copper  had  been  dis- 
solved  in  water  and  precipitated  by  sodium  hydrate, 
the   precipitate   was  dried   and   ignited,    and   it   then 
weighed  0.242  g.     What  was  the  percentage  of  copper 
in  the  salt? 

234.  A  mixture  of  4  g.  of  sodium  oxide  and  6  g.  of 
sulphur  trioxide  will  give  what  weight  of  sodium  sul- 
phate? 

235.  A  manufacturer  of  bleaching  powder  requires 
400  tons  of  chlorine.     How  much  salt,  manganese  con- 
taining 59  %  of  the  dioxide,  and  sulphuric  acid  contain- 
ing 58  °/0  of  real  acid  will  he  need  ? 

236.  What  weight  of  potassium  bromate  can  be  ob- 
tained by  neutralizing  1520  g.  of  bromine  with  potash? 

237.  lodic  acid  may  be  obtained  by  passing  a  stream 
of  chlorine  through  water  containing  iodine  in  suspen- 
sion.    How  much  iodine  and  chlorine  will  be  needed 
to  prepare  100  g.  of  iodic  acid  ? 


76       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

238.  What  weight  of  fluorspar  would  be  required 
to  furnish  sufficient  hydrogen  fluoride  (by  interaction 
with  sulphuric  acid)  to  convert   5   g.  of   quartz   into 
silicon  fluoride? 

239.  Calculate  the  weight  of  chlorine,  at   standard 
conditions,  necessary  to  give,  by  interaction  with  water, 
an  amount  of  oxygen  that  will  just  suffice  for  the  oxida- 
tion of  10  g.  of  mercury  to  mercuric  oxide. 

240.  What  weight  of  sulphuric  acid  can  be  prepared 
from  100  g.  of  sulphur  ? 

241.  Calculate  the  weight  of  potassium  in  a  sample 
of  pure  sylvite  (KC1)  which,  on  being  analyzed,  gave 
2.230  g.  of  chlorine. 

242.  What  weight  of  copper  is  present  in  a  sample 
of  pure  copper  sulphate  which,  on  being  analyzed,  gave 
30.2  g.  of  sulphur  trioxide,  SO3? 

243.  Calculate  the  percentage  purity  of  a  sample  of 
horn   silver  which,   on   being   analyzed,   gave    74.2% 
of  silver. 

244.  When  8.2  g.    of  crystallized  barium   chloride 
and  7  g.  of  sulphuric  acid  (70  %  H2SO4)  were  brought 
together  in  aqueous  solution,  what  weight  of  barium 
sulphate  was  precipitated  ? 

245.  Compare  the  weights  of   aluminum   and   zinc 
necessary  for  the  production  of  equal  weights  of  hydro- 
gen by  interaction  with  an  acid. 

246.  Compare  the  weight  of  calcium  nitride  (Ca3N2) 
(in  its  interaction  with  water)  and  the  weight  of  ammo- 
nium chloride  (in  its  interaction  with  a  base)  necessary 
to  give  the  same  weight  of  ammonia. 


WEIGHTS  FROM   EQUATIONS  77 

247.  What  relative  weights  of  cupric  oxide  and  cu- 
prous oxide  are  procurable  from  the  same  weight  of 
copper? 

248.  If  2.4  g.  of  ammonia  reduced  17  g.  of  hot  cupric 
oxide    to    copper,    calculate    the   reaction   quantity   of 
cupric  oxide  required  per  molecule  of  ammonia. 

249.  If  3  g.  of  silver  nitrate  and  1  g.  of  potassium 
chloride  were  brought  together   in   aqueous  solution, 
what  weight  of  silver  chloride  would  be  precipitated  ? 

250.  If   12   g.    of   an   alloy  of   aluminum  and   zinc 
(containing  33^  %  of  zinc)  were  placed  in  a  vessel  con- 
taining 180  g.  of  hydrochloric  acid  (35  %  HC1),  what 
volume  of  hydrogen,  at  standard  conditions,  would  be 
liberated  ? 

251.  A   specimen  of   silver   containing    3%    copper 
weighed  9.8  g.     After  solution  in  nitric  acid,  an  excess 
of  sodium  chloride    was  added   to   it.     Calculate   the 
weight  of  the  silver  chloride  precipitated. 

252.  What  weight  of  potassium  hydroxide  may  be  pre- 
pared by  the  action  of  100  g.  of  potassium  upon  water  ? 

253.  What  weight  of  potassium  will  be  required  in 
the  preparation  of  20  g.  of  potassium  carbonate  ? 

254.  What  weight  of  magnesium   chloride  may  be 
obtained  by  the  action  of  hydrochloric  acid  upon  10  g. 
of    magnesium    carbonate  ?     What    weight   of   carbon 
dioxide  will  be  liberated  ? 

255.  What  weight  of  sulphur  dioxide  can  be  obtained 
by  the  action  of  an  acid  upon  250  g.  of  sodium  sulphite  ? 

256.  If  sodium  nitrate,  ammonium  nitrate,  and  potas- 
sium nitrate  were  the  same  price  per  lb.,  which  would 
be  cheapest  to  use  for  preparing  nitric  acid,  and  why  ? 


78       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

257.  How  much  sulphuric  acid  and  potassium  nitrate 
would  be  required  in  order  to  prepare  100  g.  of  nitric 
acid? 

258.  What  weight  of  chrome-alum  may  be  obtained 
from  20  g.  of  crystallized  potassium   sulphite  and  an 
excess  of  chromium  sulphate  ? 

259.  What    weight  of  ammonium-magnesium   phos- 
phate (NH4MgPO4,  6  H2O)  could  be  formed  from  a  solu- 
tion containing  50  g.  of  crystallized  magnesium  sulphate 
and  an  excess  of  ammonia  and  sodium  phosphate? 

260.  What  weight  of  iron-ammonium  alum  may  be 
formed  when  12  g.  of  ammonium  sulphate  and  30  g. 
of  ferric  sulphate  are  brought  together  in  concentrated 
aqueous  solution  ? 

261.  When  100  g.  of  mercury  and  20  g.  of  sulphur 
are  rubbed  together,  what  weight  of  mercuric  sulphide 
may  be  formed  ? 

262.  A  solution  containing  5  g.  of  potassium  iodide  is 
precipitated  with   silver   nitrate.     What   will    be    the 
weight  of  the  precipitate  of  silver  iodide  ? 

263.  What  quantities  of   nitre  and  Chili  saltpeter, 
respectively,  will  be  required  to  obtain  the  maximum 
quantity  of  nitric  acid  by  reaction  with  140  Kg.  of  97  % 
sulphuric  acid  ? 

264.  Calculate  the  weight  of  air  required  to  burn  1 
ton  of  coal  possessing  the  following  percentage    com- 
position:  carbon,  88.42;  hydrogen,  5.61 ;  oxygen,  5.97. 

265.  How  much  marble  and  hydrochloric  acid  con- 
taining 22  %  HC1  are  needed  to  yield  10  g.  of  carbon 
dioxide  ? 


WEIGHTS  FROM   EQUATIONS  79 

266.  A  piece  of  metallic  iron  immersed  in  a  solution 
of  copper  for  a  long  time,  in  order  to  precipitate  all  the 
copper,    was    found   to   have   lost   in   weight   0.52  g. 
What  was  the  amount  of  copper  in  the  solution  ? 

267.  A  solution  of  mercuric  chloride  contains  80  g. 
of  the  salt  per  1.  ;  sodium  hydrate  is  added  in  excess  to 
175  cc.  of  the  solution  ;   what  will  the  precipitate  weigh 
if  collected  and  dried  ? 

268.  How  many  tons  of  oil  of  vitriol  containing  70  % 
H2SO4  are  needed  to  convert  100  tons  of  salt  into  salt 
cake  ? 

269.  What  increase  in  weight  will  occur  on  burning 
10  g.  of  phosphorus  in  a  tube  through  which  oxygen  is 
passed,  supposing  that  none  of  the  product  is  lost  ? 

270.  How  many  g.  of  iodine  will  be  liberated  from 
an  excess  of  a  saturated  solution  of  potassium  iodide, 
into  which  the  gas  evolved  from  heating  4.34  g.   of 
manganese  dioxide  with  hydrochloric  acid  is  passed  ? 

271.  What  weight  of  potassium  dichromate  must  be 
heated  with  hydrochloric  acid  in  order  to  evolve  suffi- 
cient chlorine  to  liberate  the  iodine  from  1.656  g.  of 
potassium  iodide  ? 


CHAPTER  VII 

Volumes  from  Equations 

1.  What  weight  of  95  %  alcohol  is  needed  to  yield 
20  m.3  of  ethylene  at  +  94°  F.  and  730  mm.? 

2.  A  1.  of  water  is  acted  upon  by  phosphorus '  tri- 
bromide;  what  will  be  the  weight  of  the  products  and 
the  volumes  of  the  gaseous  ones  at  +  4°  C.  and  760 
mm.? 

3.  A  tank  ^  m.  long,  |  m.  wide,  and  ^  m.  deep  is 
filled  with  water  and  the   water  decomposed.     What 
volumes  of  hydrogen  and  of  oxygen  result,  if  measured 
at  -13°  C.  and  790  mm.? 

4.  If   130   1.   of  CO2  are    passed   through   a   KOH 
solution,  how  many  g.  of  KOH  will  be  converted  into 
K2C03? 

5.  If  100  g.  of  Na2CO3  -are  'treated  with  HC1,  how 
many  g.    of   salt   and   how   many   1.    of    CO2  will  be 
formed  ? 

6.  If  1  m.3  of  CO2  is  absorbed  by  Ca(OH)2,  what 
weight  of  CaCO3  will  be  formed? 

7.  An  ore  contains  67  A  %  of  MnO2;  what  volume 
of  chlorine  could  be  obtained  by  treating  300  tons  of 
this  ore  with  HC1? 

8.  How  much  acetic  acid  must  be  decomposed  in 
order  to  obtain  100  1.  of  CH4? 

80 


VOLUMES  FROM   EQUATIONS  81 

9.    From  100  Ib.  of  pure  limestone  how  many  1.  of 
CO2  can  be  obtained?     What  weight  of  lime? 

10.  2  KNO3  -}-  3  C  +  S  =  3  CO2  +  N2  +  K2S.     In  the 
above  equation  find  the  weights  and  volumes  of  the 
gases  produced  and  the  weight  of  carbon  and  sulphur 
when  10  g.  of  KNO3  are  used. 

11.  How  much  phosphorus  can  be  burned  in  4  1.  of 
"  laughing  gas  "  measured  at  +  14°  C.  ? 

12.  What  weight  of  HBr  will  result   if   1    m3.    of 
hydrogen  is  caused  to   unite  with  bromine  vapor  by 
passing  the  mixture  over  a  catalytic  agent? 

13.  How  many  g.  of  zinc  are  necessary  for  the  pro- 
duction,  by  the  action  of  muriatic  acid,  of   90  1.    of 
hydrogen  measured  under  standard  conditions? 

14.  If  19  g.  of  CS2  are  burned,  what  are  the  weights 
and  volumes  of  the  products  ? 

is.  3  Cu20  +  14  HN03  =  6  Cu(NO3)2  +  7  H2O  + 
2  NO.  100  g.  of  Cu2O  are  used.  Find  volume  of  the 
gas  produced. 

16.  What  volume  of  nitrous  oxide  measured  at  0°  C. 
and  750  mm.  would  be  evolved  by  the  decomposition  of 
10  g.  of  ammonium  nitrate? 

17.  When    12  g.   of   carbon    burn    in   the  air,   find 
the  volume  of  the  resulting  gas  at  1  atmosphere  and 
0°C. 

18.  A  balloon  of  100,000  ft.3  capacity  is  to  be  filled 
with  hydrogen;   how  many  Ib.   of  zinc  and  sulphuric 
acid  will  be  needed? 

19.  How  much  water  can  be  decomposed  by  20.7  g. 
of  sodium,  and  what  volume  of  hydrogen  would  be  set 
free? 


82        PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

20.  What  volume  of  hydrogen  will  unite  with  24  g. 
of  oxygen  to  form  water  ?     What  volume  of  hydrogen 
and  of  oxygen  could  be  obtained  by  the  electrolysis  of 
10  g.  of  water? 

21.  With  what  weight   of  hydrogen  will  30  g.    of 
oxygen  unite  to  form  water? 

22.  With   how  much   sulphuric   acid  must  zinc  be 
treated  in  order  to  obtain  16,250  cc.  of  hydrogen  ?     Find 
weight  of  ZnSO4. 

23.  If  a  tube  containing  copper  oxide  weighs  before 
hydrogen  is  passed   through    it  15.846   g.,  and    after 
the  hydrogen  has  been  passed  12.239  g.,  how  many  1. 
of  hydrogen  have  united  with  the  oxygen  of  the  copper 
oxide?     How  much  water  has  been  formed? 

24.  Find  the  number  of  1.  of  gas  given  off  by  the 
action  of  130.8  g.   of  Zn  on  H2SO4. 

25.  Given  10  Kg.  of  iron  to  be  acted  upon  by  sulphuric 
acid,  what  weight  of  acid  is  needed,  and  what  is  the 
volume  of  hydrogen  secured  at  —  6°  C.  and  780  mm. 
pressure? 

26.  How  many  1.  of  hydrogen  at  0°  C.  and  760  mm. 
pressure  may  be  secured  from  2000  g.  of  HC1  ? 

27.  What  weight  of  NH4NO3  must  be  used  to  give 
45  1.  of  N2O  under  standard  conditions'? 

28.  How  many  1.  of  hydrogen,  under  standard  condi- 
tions, will  result  from  the  electrolysis  of  18  g.  of  water? 

29.  How  many  g.  of  sulphur  must  be  burned  to  yield 
100  1.  of  sulphur  dioxide  under  standard  conditions? 

30.  What  would  be  the  volume,  under  standard  con- 
ditions, of  the  hydrogen  liberated  in  the  decomposition 
of  30  g.  of  water  by  means  of  sodium  ? 


VOLUMES  FROM  EQUATIONS  83 

31.  What  volume  of  hydrochloric  acid,  under  stand- 
ard conditions,  can  be  obtained  by  the  action  of  sul- 
phuric acid  upon  150  g.  of  salt? 

32.  What  volume  of  chlorine,  measured  under  stand- 
ard conditions,  will  convert  JjO  g.  of  potassium  hydroxide 
into  chloride  and  chlorate  according  to  the  reaction : 

6  KOH  +  3  C12  =  5  KC1  +  KC1O3  +  3  H2O? 

33.  How  many  cc.  of  marble,  CaCO3  (sp.  gr.  2.70), 
must  be  dissolved  in  HC1  to  give  5  1.  of  CO2? 

34.  How  many  g.  of  air,  approximately,  ought  it  to 
take  to  burn  10  1.  of  gaseous  C3Hg,  if  ^  of  the  volume 
of  the  air  is  oxygen? 

35.  (a)  How  many  Kg.  of  CO2  will  form  in  the  com- 
bustion of  a  cylindrical  tank  of  liquid  acetylene,  C2H2, 
which  is  15  cm.   in  diameter  and  18  dm.  high,  if  its 
sp.  gr.  is  0.8?     (5)  If  the  CO2  is  absorbed  by  lime 
water,  how  many  Kg.  of  CaCO3  would  form?    (<?)  How 
many  days  will  this  tank  of  C2H2  serve  to  light  a  house 
with  6  gas  jets,  each  running  5  hours  and  burning  J  ft.3 
per  hour,  if  1  ft.3  equals  27,000  cc.? 

36.  What  volume  of  sulphur  dioxide  would  result 
from  heating  in  the  air  1  ton  of  pure  iron  pyrites,  assum- 
ing that  all  of  the  sulphur  in  the  pyrites  is  converted 
into  sulphur  dioxide  ? 

37.  What    volume    of  hydrogen    sulphide     will   be 
formed  upon  treating  40  g.  of  ferrous  sulphide,  FeS, 
with  hydrochloric  acid? 

38.  What  volume  and   what  weight  of  sulphur  di- 
oxide will  be  formed  upon  burning  1  1.   of  hydrogen 
sulphide  ? 


84       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

39.  Under  a  barometric  pressure  of  740  mm.  at  +  20° 
C.,  what  weight  of  ammonium  nitrate  must  be  decom- 
posed to  generate  sufficient  nitrous  oxide  to  fill  a  balloon 
holding  200  1.  ? 

40.  What  weight  of  carbon  will  be  required  to  com- 
pletely convert  into  carbon  dioxide  20  1.   of   oxygen 
measured  under  a  pressure  of  780  mm.  of  mercury  at 
+  30°  C.  ?     What  volume  of  carbon  dioxide,  under  the 
same  conditions,  will  be  formed  ? 

41.  Excess  of  carbon  is  thrown  into  100  g.   of  fused 
KNO3.      What   volume    of    nitrogen    and    of   CO2   is 
evolved  ? 

4  KNO3  +  50  =  2  K2CO3  +  2  N2  +  3  CO2. 

42.  Find  the  number  of  1.  of  water  needed  to  slake  a 
bin  of  lime  containing  1376  Kg. 

43.  It  is  desired  to  fill  with  oxygen  at  +  35°  C.  and 
530  mm.  a  gas-holder,  the  capacity  of  which  is  45  1. ; 
what  weight  of  KC1O3  is  requisite? 

44.  A    Kg.    of    KC1O3   will   yield   what   weight   of 
oxygen ;  what  volume  at  +  24°  C.  and  736  mm.  ? 

45.  If  256  g.  of  sodium  peroxide  are  decomposed  by 
water,  what  is  the  volume  of  the  oxygen  secured  at 
+  21°  C.  and  710  mm. ;  at  -  80°  C.  and  1410  mm.  ? 

46.  What  volume  of  hydrogen  may  be  secured  from 
12  Kg.  of  water,  with  the  aid  of  potassium,  the  hydrogen 
to  be  measured  at  +  25°  C.  and  780  mm.  ? 

47.  What   weights   of    water  and  of  potassium  are 
needed  to  generate  8  1.  of  hydrogen  at  +  25°  C.  and 
760mm.? 

48.  How    many    1.     of    hydrogen    at   +  22°  C.  and 
714  mm.  will  98  g.  of  hydrochloric  acid  yield  ? 


VOLUMES  FROM   EQUATIONS  85 

49.  How  much  zinc  is  needed  to  prepare  100  1.   of 
hydrogen  at  0°  C.  and  740  mm.  ? 

50.  Am.3  gas-holder  is  to  be*  filled  with  oxygen  at 
+  100°  C.   and  721  mm.     What  weight   of  Pb(NO3)2 
is  needed  to  prepare  it? 

51.  If  10  1.  of  hydrogen  at  +  15°  C.  are  burned,  what 
volume  of  steam  at  +  300°  C.  is  formed? 

52.  How    many   1.    of   chlorine  can  be  obtained  by 
treating  50  g.  of  manganese  dioxide  with  hydrochloric 
acid? 

53.  What  volume  of  arsine  will  result  when  150  mg. 
arsenic  trioxide  is  acted  upon  by  nascent  hydrogen? 

54.  How  much  lead  sulphide  can  be  precipitated  by 
17  1.  of  hydrogen  sulphide  ? 

55.  What  volume  of  sulphur  vapor  would  result  from 
the  decomposition  of  a  1.  of   H2S  at  +  500°  C.   if  the 
density  of  S  is  96  and  its  atomic  weight  is  32  ? 

56.  What   volume    of   zinc    vapor    will   unite    with 
300  cc.  of  oxygen  to  form  zinc  oxide?     Zn  has  vapor 
density  of  32.5;  atomic  weight  65. 

57.  How  much  phosphoric  fluoride  by  volume  can 
be  obtained  from  100  g.  of  phosphorus  pentachloride  ? 

5  AsF3  +  3  PC15  =  5  AsCI3  +  3  PF5. 

Supposing  all  the  products  to  be  gases,  find  the  vol- 
umes. 

58.  How  many  cc.  of  solid  arsenic  (sp.  gr.  5.73)  could 
be  obtained  from  1250  cc.  of  arsine  at  a  temperature  of 
+  105°C.? 

59.  If  425  1.  and  328  cc.  of  oxygen  at  +  24°  C.  and 
658  mm.  are  wanted,  what  weight  of  BaO2  is  needed 
to  make  that  amount  ? 


86       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

60.  If  752  1.  of  oxygen  at  +  19°  C.  and  729  mm.  are 
wanted,  what  weight  of  water  must  be  decomposed  to 
secure  that  amount,  and  what  volume  of  hydrogen  is 
obtained  at  the  same  time  ? 

61.  Three  1.  of  water  are  to  be  decomposed.     What 
volumes  of  hydrogen  and  oxygen  result  at  —  21°  C.  and 
790  mm.  ? 

62.  The  hydrogen  secured  from  100  Ib.  of  sulphuric 
acid  is  burned.      What  weight  of  water  results  ? 

63.  The   hydrogen   derived    from   2  1.    of   water  is 
burned.     What  is  the  weight  of  the  product? 

64.  The  hydrogen  derivable  from  98  Kg.  of  pure  sul- 
phuric acid  is  to  be  burned ;   what  is  the  weight  of  the 
product?    What  is  its  volume  at  +  4°  C.  and  760  mm. ; 
at  +  150°  C.  and  754  mm.  ? 

65.  How  much  ammonium  nitrate  is  needed  to  pre- 
pare 100  1.  of  nitrous  oxide  at  —  5°  C.  and  600  mm.  ? 

66.  How  much  copper  is  needed  to  prepare  100  1.  of 
nitric  oxide  at  -  100°  C.  and  760  mm.  ? 

67.  What  weight  of  phosphorus,  if  all  is  converted, 
is  necessary  to  produce  100  1.  of  phosphine  at  +  68°  F. 
and  720  mm.  ? 

68.  What  volumes  of  hydrogen  and  oxygen,  respec- 
tively, result  from  the  decomposition  of  100  1.  of  water 
vapor  at  +  200°  C.  ? 

69.  What  weight  of  carbon  is  necessary  to  reduce.  20 
g.  of  carbon  dioxide  to  carbon  monoxide  ?     How  many 
1.  of  air  at  +  22°  C.  and  760  mm.  are  required  to  burn 
the  monoxide  thus  formed  to  the  dioxide  ? 


VOLUMES  FROM  EQUATIONS        87 

70.  What  volume  of  oxygen,  measured  under  stand- 
ard conditions,  will  be  evolved  when  108  g.  of  mercuric 
oxide  are  decomposed  by  heating  ? 

71.  If  15  Kg.  of  H2SO4  are  worked  up  by  the  aid  of 
copper  into  sulphur  dioxide,   what   weight   of    Cu  is 
needed,  and  what  weights  and  volumes  of  the  products 
result  at  +  35°  C.  and  730  mm.  ? 

72.  A  1.  of  chlorine  measured  at  +  25°  C.  and  753 
mm.  is  used  to  expel  the  iodine  from  potassium  iodine. 
What  weight  of  iodine  is  expelled  ? 

73.  Find,  under  standard  conditions,  the  volume  of  the 
gases  resulting  from  the  electrolysis  of  72  g.  of  water. 

74.  If  50  gal.  of  carbon  monoxide  are  burned,  what 
volume  of  oxygen  at  +  48°  C.  and  675  mm.  is  necessary, 
and  what  volume  of  carbon  dioxide  is  secured  ? 

75.  One  hundred  g.  of  chlorine  are  to  be  united  with 
hydrogen.     What  volume  of   hydrogen   is  needed   at 
4-  150°  C.  and  735  mm.,  and  what  volume  of  hydro- 
chloric acid  gas  results  ? 

76.  The  hydrogen  sulphide  secured  from  55  Kg.  of 
ferrous  sulphide  is  decomposed.    What  volume  of  hydro- 
gen results  at  0°  C.  and  760  mm. ;  at  +  75°  C.  and  780 
mm.? 

77.  If  1500  g.  of  HC1  are  decomposed,  what  volumes 
of  H  and  of  Cl  are  secured  at  +  28°  C.  and  790  mm.  ? 

78.  The  HC1  securable  from  550  g.  of  common  salt  is 
decomposed.     What  volumes  of  H    and  Cl  result   at 

-20°C.  and  778  mm.? 

79.  The  water  resulting  from  the  combustion  of  1  g. 
of  hydrogen  is  decomposed.     What  are  the  volumes  of 
H  and  O  at  +  4236  C.  and  787  mm.  ? 


88       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

80.  What  weight  of  material  is  required  to  secure 
500  1.  of  ammonia  at  0°  C.  and  700  mm.  ? 

81.  If  500  g.  of  oxalic  acid  are  decomposed  with  sul- 
phuric  acid,   what  volumes   of  carbon   monoxide    and 
dioxide  result  if  measured  at  —  21°  F.  and  640  mm.  are 
obtained  ? 

82.  How  much  ferrous  sulphide  is  needed   to  pre- 
pare 100  1.  of  hydrogen  sulphide  at  - 10°  C.  and  800 
mm.  ? 

83.  If  13,720  cc.  of  hydrogen  chloride  at  -  10°  C. 
and  730  mm.  are  decomposed  by  electricity,  what  are 
the  volumes  and  weights  of  the  products  ? 

84.  What  weight  of  calcium  carbide  must  be  em- 
ployed if  we  wish  to  fill  with  acetylene  gas  a  reservoir, 
12  m.  by  10  m.  by  60  cm.,  at  +  28°  C.  and  760  mm.  ? 

85.  What  volume  of  nitrous  oxide,  measured  at  0°  C. 
and  780  mm.,  may  be  obtained  from  10  Kg.  of  ammonium 
nitrate  ? 

86.  How  many  1.  of  chlorine  at  -}-  21°  C.  and  750  mm. 
are  needed  to  manufacture  10  Kg.  of  potassium  chlorate, 
provided  there  is  no  loss  ? 

87.  What  weight  of  calcium  carbide  must  be  em- 
ployed to  fill  with  acetylene  gas  a  gas-holder  that  con- 
tains 10,000  m.3  at  + 18°  C.  and  750  mm.  ? 

88.  The  hydrogen  chloride  secured  from  210  Kg.  of 
sodium  chloride  is  employed  for  preparing  hydrogen. 
What  is  the  volume  procurable  at  +1200°C.  and  2.5 
atmospheric  pressure  ? 

89.  What  volume  of  hydrogen  at  -f  40°  C.  and  715 
mm.  will  1  Kg.  of  sodium  liberate  from  water? 


VOLUMES  FROM  EQUATIONS  89 

90.  What  volume  of  arsine  at  +20°  C.  and  760  mm. 
results  from  the  action  of  nascent  hydrogen  upon  10  g. 
of  arsenious  oxide  ? 

91.  What  volume  of  hydrogen  sulphide  at  +  110°  C. 
and  660  mm.  may  be  made  from  210  Kg.  of  ferrous  sul- 
phide ? 

92.  What  volume  of  NH3  may  be  obtained  from  430  g. 
of  NH4C1? 

93.  What  volume  of  oxygen  is  needed  at  0°C.  and 
760  mm.  to  burn  completely  42  1.  of  hydrogen  sulphide 
measured  at  +  20°  C.  and  780  mm.? 

94.  A  container  measuring  50  cm.  by  9  dm.  by  300 
mm.  is  filled  with  HC1  gas  at  +  20°  C.   and  740  mm. 
A  precisely  similar  measure  of  ammonia  is  introduced ; 
what  weight  of  ammonium  chloride  is  formed  ?     What 
is  left  over  and  how  much  ? 

95.  What  volume  of  gaseous  products,  measured  at 
4- 150°  C.  and  760  mm.,  is  secured  by  the  decomposition 
by  heat  of  2  Kg.  of  ammonium  nitrate  ? 

96.  One  Kg.  of  phosphorous  acid  is  to  be  made  by 
acting  upon  phosphorus  tribromide  with  water.     What 
weight  of  the  tribromide  is  needed,  and  what  volume  of 
hydrogen  bromide  is  produced  ? 

97.  If  1300  1.  of  hydrogen  sulphide  at  +88°C.  and 
742  mm.  are  decomposed,  what  weight  of  sulphur  re- 
sults?    What  is  the  volume  of  the  resultant  sulphur 
measured  at  +1450°  C.  and  760  mm.? 

98.  What  volumes  of  hydrogen  and  nitrogen,  meas- 
ured at  —  10°  C.  and  730  mm.,  result  if  we  decompose 
by  electricity  all  of  the  ammonia  that  may  be  secured 
from  1000  g.  of  ammonium  sulphate  ? 


90       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

99.  Given  20  1.  of  sulphur  vapor  at  +  500°  C.,  what 
quantity,  by  weight,  of  sulphur  trioxide  can  be  made 
from  it  ? 

100.  To  secure  100  Kg.  of  H2S  at  - 10°  C.  and  750 
mm.,  what  weight  of  Na2S  and  of  hydrochloric  acid  is 
needed  ?     And  what  other  products  are  secured? 

101.  How  many  g.  of  sulphur  are  needed  to  produce 
110  1.  of  sulphur  dioxide  at  +  360°  F.  and  739  mm.? 

102.  If  10,000  m.3  of  hydrogen  sulphide  at  two  at- 
mospheres  pressure    and    + 10°  C.   are    wanted,    what 
weight  of  materials  is  needed  to  make  it  ? 

103.  What  volume  of  hydrogen  chloride  is  formed 
when  10  1.  of  chlorine  combine  with  hydrogen  ? 

104.  What  volume  of  nitric  oxide,  measured  at  743 
mm.  and  + 18°  C.,  will  be  produced  by  treating  18  g. 
of  metallic  copper  with  an  excess  of  nitric  acid  ? 

105.  How  many  1.  of  oxygen  are  required  to  burn 
3  1.  of  AsH3,  and  what  will  be  the  weight  of  each  of 
the  products  ? 

106.  What  volume  of  carbon  dioxide,  measured  at 
750  mm.  pressure  and  +20°C.,  will  be  formed  when 
17  g.  of  a  candle,  85  %  C  and  15  %  H,  is  burned  ? 

107.  A   steel   cylinder   of   4   ft.3  capacity  is   to  be 
filled  with  carbon  dioxide  under  a  pressure  of  150  Ib. 
to  the  in.2.     What  weight  of  marble  and  hydrochloric 
acid  would  be  needed  to  produce  the  necessary  amount 
of  gas  ? 

108.  How  many  1.  of  acetylene  can  be  obtained  from 
50  g.  of  calcium  carbide  that  is  93  %  pure,  if  the  gas  is 
evolved  at  a  temperature  of   +  40°  C.  and  a  pressure 
of  1 J  atmospheres  ? 


VOLUMES  FROM   EQUATIONS  91 

109.  What  volume  of  sulphur  dioxide  at   +  20°  C. 
and  740  mm.  can  be  obtained  by  the  action  of  20  g. 
of  sulphuric  acid  upon  copper  ? 

110.  How  many  1.  of  carbon    dioxide  would  result 
from  burning  5.384  g.  of  carbon? 

111.  What  volume  of   oxygen  will  be  required  to 
burn  1  Kg.  of  carbon  ? 

112.  What  volume  of  air,  of  21  %  oxygen  by  volume, 
is  needed  to  burn  completely  1  ton  of  anthracite  coal, 
assumed  to  be  pure  carbon  ? 

113.  How  many  1.  of  chlorine  can  be  obtained  from 
34  g.  of  salt  ? 

114.  What  volume  of  oxygen,  measured  at  + 15°  C. 
and  772  mm.  pressure,  can  be  obtained  from  100  cc.  of 
sulphuric  acid  (sp.  gr.  1.84)? 

2  K2Cr207  +  8  H2S04  =  2  K2SO4  +  2  Cr2(SO4)3 

+  8  H20  +  3  02. 

115.  How  many  1.  of  air  will  be  required  to  burn 
5  g.  of  phosphorus? 

116.  If  10  1.  of  hydrofluoric  acid  gas  were  made  from 
CaF2  and  H2SO4,  how  much  CaSO4  was  made  at  the 
same  time? 

117.  What   volume    of   nitrous  oxide,  measured   at 
0°  C.  and  750  mm.,  would  be  evolved  by  the  decomposi- 
tion of  10  g.  of  ammonium  nitrate  ? 

118.  What  volume  of  carbon  dioxide,  under  standard 
conditions,    can   be    obtained   from    exactly   10   g.    of 
calcium  carbonate? 

119.  If  12  g.  of  carbon  are  burned  to  carbon  dioxide, 
what  will  be  the  volume  of  the  gas  compared  with  1  g. 
of  hydrogen  at  the  same  temperature  and  pressure  ? 


92       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

120.  From  2078  g.  of  sodium  chloride  what  volume 
of  chlorine  can  be  obtained  ? 

121.  If   9.6  g.  of   sulphur  are  heated  in  hydrogen, 
what  volume  of  hydrogen  sulphide  is  formed  ? 

122.  What  volume  of  hydrogen,  under  normal  condi- 
tions of  temperature  and  pressure,  can  be  obtained  from 
10  £.  of  pure  zinc  ? 

123.  Calculate  the  number  of  g.  of  ferrous  carbonate 
required  to  react  with  sulphuric  acid  in  order  to  set 
free  60  1.  of  carbon  dioxide. 

124.  If  40  g.  of  Ca  react  with  water,  what  is  the 
weight  and  volume  of  hydrogen? 

125.  If   600  g.  of   MnO2   are    decomposed  by  heat, 
what  is  the  volume  of  O  at  +  13°  C.  and  781  mm.  ? 

126.  If  55.8  1.  of  hydrogen  at  0°  C.  and  760  mm. 
are  required,  how  much   zinc   and   KOH   are  needed 
for  its  formation  ? 

127.  If  168  g.   of  MgCO3  are  heated  and  the  CO2 
is  passed  into  KOH  solution,  what  weight  of  K2CO3 
will  be  formed  ? 

128.  If  147  g.  K2Cr2O7  are  heated  with  H2SO4,  what 
will  be  the  volume  and  weight  of  gas  evolved  ? 

129.  How  much  alcohol  should  be  burned  to  give 
13  1.  of  steam  ? 

130.  If  1000   cc.  of  H2S  burn  in  the  air,  find  (a) 
weight  and  volume  of  oxygen  used,  and  (b)  products 
formed. 

131.  If  16  1.  of  SO2  are  produced  by  burning  a  piece 
of  sulphur,  how  heavy  was  the  sulphur  ? 

132.  What  volume  of  chlorine  is  required  to  unite 
with  71  g.  of  gold  to  produce  auric  chloride  ? 


VOLUMES  FROM  EQUATIONS  93 

133.  How  many  1.  of  oxygen  at  0°  C.  and  760  mm. 
could  be  obtained  from  a  pailful  of  water,  the  water 
weighing  12  Kg.  ? 

134.  How  much  salt  is  necessary  to  produce  480  g. 
of  chlorine,  and  how  much  space  would  be  filled  by  that 
amount  of  chlorine  at  +  20°  C.  and  755  mm.  pressure  ? 

135.  The  sp.  gr.  of  acetylene  is  0.92.     What  volume 
would  be  occupied,  at  +  20°  C.  and  750  mm.,  by  the 
gas  generated   from  480  g.  of   calcium   carbide,  95  % 
pure? 

136.  What  weight  of  potassium  chlorate  is  necessary 
to    yield    6    1.    of    oxygen    measured    over   water   at 
+  18.1°  C.  and  759.9  mm.? 

137.  If  2  g.  of  steam  are  passed  over  red-hot  iron, 
what  volume  of  hydrogen  at  +  10°  C.  and  770  mm.  is 
formed  ? 

4  H20  +  3  Fe  =  Fe3O4  +  4  H2. 

138.  What  weight  of  sodium  would  be  necessary  to 
liberate  75  cc.  of  hydrogen  at  0°  C.  and  760  mm.  by 
reacting  with  water  ? 

139.  What  volume  of  oxygen  at  0°  C.  and  760  mm. 
would   be   liberated   by  heating   1.05   g.   of   mercuric 
oxide  ? 

140.  What  volume  of  hydrogen,  measured  over  water 
at  +  17.3°  C.  and  758.2  mm.,  will  be  generated  by  the 
reaction  of  20  g.  of  zinc  with  dilute  sulphuric  acid  ? 

141.  What  volume  of  "laughing  gas,"  measured  at 
4-  20°  C.  and  750  mm.,  may  be  made  from  12  g.  of 
ammonium  nitrate  ? 

142.  How  much  phosphorus  is  required  to  remove 
the  oxygen  from  a  1.  of  air  ? 


94       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

143.  How  much  alcohol  will  be  needed  to  use  up 
during  combustion  116  g.  of  oxygen  ? 

144.  Find  the  volume  of  oxygen  needed  to  burn  com- 
pletely 20  g.  of  alcohol  and  the  volumes  of  the  products. 

145.  What  volume  of  phosphine  is  evolved  during 
the  solution  of  62  g.  of  phosphorus  in  Ba(OH)2  solu- 
tion ? 

146.  Calculate   the  volume   of   ammonia   obtainable 
from  126  g.  of  HNO3. 

147.  If  5580  cc.  of  HF  are  passed  over  heated  so- 
dium, how  much  of  each  product  is  obtained? 

148.  An  excess  of  Ag2O  is  thrown  into  136  g.  of  a 
solution  of  H2O2  containing  75  %  water ;  what  gas  is 
evolved,  and  what  will  be  its  volume  at  — 133°  C.  and 
1520  mm.  ? 

149.  If  55  g.  of  HgO  are  heated,  what  is  the  volume 
of  the  oxygen  at  667  mm.  and  +  22°  C.  ? 

150.  To  produce  112  1.  of  hydrogen  from  steam,  how 
much  charcoal  must  be  used? 

151.  MnO2    is   treated    with    10   1.    of    HC1.     Find 
weight  and  volume  of  chlorine  produced. 

152.  What  weight  of  ammonium  sulphate  would  be 
produced  by  neutralizing  100  g.  of  pure  sulphuric  acid 
with  ammonia? 

153.  How  much   carbon   dioxide  by  weight  and  by 
volume  can  be  prepared  from  275  g.  of  calcium  carbon- 
ate? 

154.  What  volume  of  chlorine  at  + 15°  C.  must  be 
passed  over  20  g.  of  AgNO3  to  obtain  N2O5? 

C12  +  2  AgN03  =  2  AgCl  +  0  +  N2O5. 


VOLUMES  FROM   EQUATIONS  95 

155.  What  volume  of  H2S  would  be  needed  to  pro- 
duce 10  g.  of  CuS  from  a  CuSO4  solution? 

156.  Calculate  the  volume  of  carbon  dioxide,  meas- 
ured at  0°  C.  and  760  mm.,  that  can  be  made  from  50  g. 
of  calcium  carbonate  and  an  excess  of  hydrochloric  acid. 

157.  Into  what  volume  of  oxygen  will  96  g.  of  ozone 
break  up? 

158.  If  500  g.  of  hydrogen  are  needed,  how  much 
steam  is  required? 

159.  If  5  g.  of  zinc  are  dissolved  in  acid,  how  many 
cc.  of  hydrogen  are  freed  when  measured  at  + 10°  C. 
and  750  mm.  ? 

160.  How   many   cc.    of   HC1    solution,    containing 
240  g.  of   HC1  per  1.,  will  be  required  to  decompose 
2500  g.  of  CaCO3? 

161.  How  many  1.  of  (a)  hydrogen  and  (5)  carbon 
monoxide,  at  +  10°  C.  and  750  mm.,  can  be  obtained 
by  passing  steam  over  24  g.  red-hot  charcoal  ? 

162.  If  13  g.  of  sodium  are  placed  on  water,  the  con- 
ditions being  +  11°  C.  and  700  mm.,  how  many  m.3  of 
gas  are  liberated? 

163.  If  2  g.  of  potassium  are  heated  in  NH3,  how 
much  potassium  amide  and  what  volume  of  hydrogen 
at  +15°  C.  are  formed? 

K  +  NH8  =  KH2N  +  H. 

164.  What  weight  of  nitric  oxide  would  be  needed 
to  unite  with  the  oxygen  of  the  air  in  a  10  1.  flask? 

165.  If  a  man  exhale  one  m.3  of  CO2  in  an  hour,  at 
+  16°  C.,  how  long  will  it  take  him  to  produce  5  Kg. 
of  the  gas? 


96       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

166.  When  10  g.   of   sulphur  burn  in  contact  with 
hydrogen,  what  volume  and  weight  of   H2S  could  be 
produced? 

167.  If  2  1.  of  nitrosyl  chloride  at  -f- 15°  C.  are  passed 
over  warm  lunar  caustic,  how  much  N2O5  is  formed? 

NO2C1  +  AgNO3  =  AgCl  +  N2O5. 

168.  A   balloon   holds    15,000   1.     What   weight   of 
NH4NO3   will   give  enough  gas  to  fill  the  balloon  at 
+  20°  C.  and  600  mm.  ? 

169.  Find  weight  of  copper  needed  to  produce  15  1. 
of  NO  at  871  mm.  and  +  22°  C. 

170.  If  20  1.  of  oxygen  under  420  mm.  pressure  will 
be  enough  to  burn  completely  20  g.  of  phosphorus,  at 
what  temperature  is  it? 

171.  If  300  cc.  of  NH3  react  with  chlorine,  what  volume 
of  nitrogen  is  obtained  at  —6°  C.  and  327  mm.  pressure? 

172.  What  volume  of  hydrogen  is  required  by  19  g. 
of  chlorine  to  produce  hydrochloric  acid  ? 

173.  If  300  cc.  of  chlorine  are  obtained  from  the  elec- 
trolysis of  HC1,  what  weight  and  volume  of  hydrogen 
are  given  off,  and  what  weight  of  HC1  is  used? 

174.  If  130  g.  of  pyrolusite  (90.7  %  pure)  are  heated 
with  an  excess  of  HC1,  what  is  the  volume  of  the  gas 
given  off? 

175.  A  tank  contains  6m.3.     How  many  g.  of  zinc 
and  acid  are  needed  to  fill  it  with  hydrogen  at  standard 
conditions? 

176.  If  1  g.  each  of  K,  Li,  Na,  and  Ca  are  placed  in 
water  separately  and  the  hydrogen  of  each  is  measured, 
which  metal  will  give  the  greatest  yield  in  cc.  ?     Find 
weight  from  each. 


VOLUMES  FROM  AQUATIONS  97 

177.  Find  weight  of  171.  of  ethylene.     What  volume 
of  oxygen  would  be  needed  to  burn  it  ? 

178.  How  many  g.  and  1.  of  oxygen  will  be  given  by 
300  g.  of  K2Cr2O7  +  H2SO4  in  excess  ? 

179.  How  many  1.  of  chlorine  will  be  liberated  by 
treating  39  g.  of  KC1O3  with  sufficient  HC1  solution  to 
decompose  it? 

180.  If   98   g.  of    H2SO4   react   on    K2Cr2O7,    what 
volume  of  oxygen,  measured  at  +  12°  C.  and  T99  mm., 
will  be  evolved  ? 

181.  Calculate   the  weight  of   NH4NO3  required  to 
produce  1900  cc.  of  N2O,  measured  at  +  12°  C.  and  710 
mm. 

182.  If  500  g.  of  marble  are  treated  with  HC1,  how 
many  g.   of   HC1  are    needed,   and   what    will  be  the 
volume   of    the    resulting    gas    at    + 15°  C.    and   740 
mm.? 

183.  How  many  1.  of  muriatic  acid  will  be  liberated 
by  treating  585  g.  of  salt  with  H2SO4? 

184.  The  iodine  in  100  volumes  of  HI  is  liberated  in 
succession  by  chlorine  and  oxygen.     Find  the  volume 
of  chlorine  and  of  oxygen  used. 

185.  How  much  SnCl2  must  be  electrolyzed  to  give 
chlorine   enough   to    convert   180  g.  of  antimony  into 
SbCl3? 

186.  When  100  g.  of  NH4NO3  are  decomposed,  find 
the  volume  of  N2O  measured  at  -f 1°  C.  and  800  mm. 

187.  If  50  g.  of  CO  are  needed,  what  volume  of  CO2 
should  be  passed  over  red-hot  coke  ? 

188.  What  volume  of  H2S,  measured  at  —31°  C.  and 
777  mm.,  can  be  obtained  from  10  g.  of  FeS? 


98       PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

189.  What  volume  of  chlorine  at  +27°  C.  and  777 
mm.  will  be  required  to  convert  232  g.  of  Bi2O3  into 
Bi208? 

190.  What  volume  of  NH3  will  50  g.  of  lime  liberate 
from  an  ammonia  salt? 

191.  What  volumes  and  weights  of  hydrogen   and 
oxygen  are  contained  in  13  1.  of  water? 

192.  If  10  g.  of  graphite  burn  in  oxygen,  what  is  the 
weight  and  volume  of  CO2  formed? 

193.  What  weight  of  salt  will  yield  (a)  17  1.  chlo- 
rine;  (6)  13  g.  Na2SO4;   (c)  30  g.  MnSO4;    (d)  3  1.  of 
water  ? 

194.  If  30  cc.  of  air  and  60  cc.  of  hydrogen  are  ex- 
ploded, what  is  the  volume  and  weight  of  the  residue  ? 

195.  If  16  g.  of  HgO  are  heated,  what  is  the  weight 
of  residue;  the  weight  and  volume  of  gas  given  off? 

196.  If  100  g.  of  steam  are  passed  over  red-hot  iron, 
what  volume  of  hydrogen  at  +10°  C.  and  742  mm.  is 
formed  ? 

197.  What  volume  of  oxygen  can  be  obtained  from 
20  g.  of  manganese  dioxide  by  heating  it  alone? 

198.  What  volume  of  oxygen  at  +10°  C.  and  743 
mm.  can  be  obtained  by  the  decomposition  of  a  1.  of 
sulphuric  acid  possessing  a  density  of  1.84  at  0°  C.? 

199.  What  weight  of  hydrochloric  acid  is  produced 
in    the  manufacture  of  100  tons  of  salt  cake?     What 
volume  of  gas  escapes,  supposing  the  manufacturer  to 
condense  only  92  %  of  the  quantity  evolved? 

200.  What  volume  of  oxygen  at  0°  C.  and  760  mm. 
can  be  theoretically  obtained  from  1  Ib.  of  bleaching 
powder  ? 


VOLUMES  FROM  EQUATIONS  99 

201.  If  1  g.  of  phosphorus  is  to  be  converted  into 
the   pentachloride,    how    many   1.   of  chlorine  are   re- 
quired? 

202.  How  much  marble  and  hydrochloric  acid  con- 
taining 22  %   HC1  are  needed  to  yield  10  1.  of  carbon 
dioxide  at  +  15°  C.  and  760  mm.  barometric  pressure? 

203.  Calculate  the  volume  of  nitrogen  monoxide  at 
+  15°  C.  and  740  mm.  produced  on  heating  30  g.  of 
ammonium  nitrate. 

204.  I  require  10  1.  of  carbon  monoxide  at  0°  C.  and 
760°  mm.  pressure.     How  many  g.  of  (a)  oxalic  acid; 
(6)  of  formic  acid ;    and  (c)  of  potassium  ferrocyanide 
shall  I  need  ? 

205.  A  gas  bag  has  a  capacity  of  45  1. ;  how  much 
manganese  dioxide  containing  70  %  of  MnO2  is  required 
to  fill  it  with  oxygen  at  4-15°  C.  and  760  mm.? 

206.  How  many  cc.  of  oxygen  and  hydrogen,  measured 
at  +12°  C.  and  under  a  pressure  of  762  mm.,  can  be 
obtained  by  the  electrolysis  of  10  g.  of  water? 

207.  What  weight    of   ammonia   and  of   chlorine  is 
needed  to  produce  a  1.  of  nitrogen  ? 

208.  If  100  g.  of  steam  are  passed  over  1000  g.  of 
red-hot  iron  wire,  what  volume  of  hydrogen  is  evolved, 
measured  at  +  10°  C.  and  742  mm.,  and  what  weight  of 
iron  oxide  is  produced  ? 

209.  Find  weight  of  hydrogen  needed  to  unite  with 
21  g.  of  oxygen  to  form  water.     How  much  with  (a) 
20ff.;(i)76g.;O)300g.? 

210.  How  many  g.   of  mercury  and  how  many  1.  of 
chlorine,  measured  at  a  temperature  of  -f-  16°  C.  when 
the  barometer  stands  at  770  mm.,  are  consumed  in  the 
manufacture  of  100  g.  of  corrosive  sublimate? 


100     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

211.  Find  the  volume  of  HF  from  71  g.  of  CaF2  and 
enough  H2SO4. 

212.  What  weight  of  NH4OH  is  needed  to  produce 
131  i.  of  NH3? 

213.  How  many  g.  of  CaCO3  will  produce  114  1.  of 
C02? 

214.  How  much  sodium  acetate  and  caustic  soda  is 
needed  to  yield  300  cc.  of  CH4? 

215.  If  8  g.  of  methyl  alcohol  burn  in  air,  what  vol- 
ume of  oxygen  is  used,  and  what  are  the  weights  of  the 
products  ? 

216.  What  weight  and  volume  of  chlorine  is  produced 
by  treating  300  g.  of  HC1  with  enough  HNO3? 

217.  How  many  g.  of   acid  calcium  carbonate  will 
200  1.  of  CO2  with  water  produce  from  CaCO3? 

218.  What  volume  of  nitrogen,  measured  at  —  1°  C. 
and  800  mm.,  is  given  off  on  heating  84  g.  ammonium 
dichromate  ? 

219.  When  2  g.  of  sulphur  are  burned  in  a  closed 
vessel  containing  16  1.  of  air  (21  %  O),  what  volumes 
of  oxygen  and  sulphur  dioxide  are  present  after  com- 
bustion ? 

220.  How  much  calcium  will  liberate  56  1.  of  hydro- 
gen from  water? 

221.  When  83  g.  of  cobaltic  oxide  are  heated  with 
HC1,  what  volume  of  chlorine  is  evolved? 

222.  A  balloon  holds  200   Kg.  of  hydrogen.     How 
much  Zn  and  HC1  are  needed?     Find  volume  of  hydro- 
gen at  +  90°  C.  and  760  mm. 

223.  A  room  is  6  m.  x  760  cm.  x  896  mm.     Find  the 
weight  of  air  in  the  room. 


VOLUMES  FROM   EQUATIONS  101 

224.  A  room    30  m.  x  18  m.  x  15  m.    is   filled    with 
oxygen.     What  weight  of  gas  does  it  contain  ? 

225.  What  volume  at  +  20°  C.  and  under  a  pressure 
of  two  atmospheres  will  100  1.  of  sulphur  dioxide,  meas- 
ured at  0°  C.  and  under  a  pressure  of  one  atmosphere, 
occupy?     What  weight  of  sulphur  is  necessary  to  pro- 
duce this  amount  of  sulphur  dioxide? 

226.  When    10  g.   of  turpentine    are   burned,  what 
volume  of  carbon  dioxide  is  formed? 

227.  How  many  1.  of  hydrogen  are  obtained  on  dis- 
solving 16  g.  of  magnesium  in  dilute  sulphuric  acid  ? 

228.  How  many  1.  of  hydrochloric  acid  can  be  made 
by  the  use  of  575  g.  of  KC1? 

229.  When  1  g.  of  HgO  and  1  g.  KC1O3  and  1  g. 
Pb(NO3)2  are  each  heated  separately  and  the  oxygen  is 
measured,  calculate  the  weight  and  volume  in  each  case. 

230.  How  much  ozone  will  13  g.  of  oxygen  make? 
What  residue  and  how  much  will  there  be  ? 

231.  How  much  carborundum  will  2  tons  of  sand 
make ?    What  volume  of  CO  will  be  produced  ?    (SiO2  + 
3  C  =  SiC  +  2CO). 

232.  Find  the  volume  of  HF  which  may  be  produced 
from  300  g.  of  CaF2  at  -  6°  C.  and  791  mm. 

233.  If  10  1.  of  carbon  monoxide  at   + 14°  C.  and 
760  mm.  are  required,  what  volume  o*f  carbon  dioxide 
must  be  passed  over  red-hot  carbon,  and  what  mass  of 
carbon  is  used? 

234.  How  many  1.    of  hydrogen  phosphide  can  be 
made  by  the  use  of  250  g.  of  calcium  phosphide? 

235.  How  many  1.  of  hydrogen  arsenide  can  be  made 
with  640  g.  of  zinc  arsenide? 


102     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

236.  How  many  1.  of  hydrogen  and  of  oxygen  are 
necessary  to  produce  10  cc.  of  liquid  water? 

237.  How  many  g.   of  chalk  are  required  to  yield 
15  1.  of  choke  damp? 

238.  How  many  cc.  of  chlorine  at  a  temperature  of 
+  15°  C.  and  under  a  pressure  of  770  mm.  can  be  ob- 
tained from  150  g.  of  silver  chloride? 

239.  How  much  cryolite  is  needed  to  prepare  100  1. 
of  hydrogen  fluoride  at  +  100°  C.  and  500  mm.? 

240.  When  250  cc.  of  carbon  dioxide  are  passed  over 
red-hot  carbon,  what  volume  of  carbon  monoxide  will 
be  formed? 

241.  A  room  is  25  m.  long,  15  m.  broad,  and  10  m. 
high ;  how  much  carbon  dioxide  will  it  contain  at  the 
rate  of  4  volumes  in  10,000? 

242.  What  weight  in  g.  of  sodium  acetate  is  required 
to  yield  10  1.  of  methane  at  +  20°  C.  and  760  mm.  ? 

243.  A  piece  of  charcoal  is  burned  in  2  J  1.  of  oxygen  ; 
how  many  1.  of  carbon  dioxide  will  be  formed,  and  how 
much  will  the  carbon  dioxide  weigh? 

244.  If  I  wish  to  obtain  1  1.  of  oxygen  by  heating 
mercuric  oxide,  what  weight  of  the  oxide  shall  I  need? 

245.  What  volume  of  chlorine  would  exactly  decom- 
pose 25  g.  of  hydriodic  acid  ? 

246.  What  weight  of  copper  and  sulphuric  acid  is 
needed  to  yield  3  1.  of  SO2? 

247.  What  is  the  weight  of  25  1.  of  carbon  dioxide, 
and  what  weight  of  pure  baking  soda  would  be  required 
to  prepare  it? 

248.  Phosphorus  is  burned  in  15  1.  of  nitrous  oxide ; 
how  many  1.  of  nitrogen  will  remain? 


VOLUMES  FROM  EQUATIONS  103 

249.  What  volume  of  hydrogen,  measured  over  water 
at  +  18°  C.  and  746.4  mm.,  will  be  liberated  by  the 
action  of  aluminum   upon  20  g.  of  sulphuric  acid  con- 
taining 41.5  %  H2SO4? 

250.  An  unknown  volume  of  hydrogen  sulphide  re- 
quired 110.34  cc.  of  chlorine  for  complete  decomposi- 
tion.    What  was  the  volume  of  the  hydrogen  sulphide? 

251.  What  volume  of  hydrobromic  acid  at  +  15°  C. 
and  770  mm.  pressure  would  be  produced  by  the  action 
of  water  upon  50  g.  of  phosphorus  tribromide  ? 

252.  What  volume  of  oxygen  would  be  required  for 
the  complete  combustion  of  120  g.   of  bisulphide  of 
carbon? 

253.  What  volume  of  oxygen  would  be  required  for 
the  combustion  of  125  g.  of  boron? 

254.  If    20    g.    of    a    silicate    containing    20%     of 
silica  are  heated  with  fluorspar  and  strong  sulphuric 
acid,  what  volume  of  silicon  fluoride  will  be  produced  ? 

255.  What  weight  of  materials  would  be  required  to 
prepare  10  1.  of  chlorine? 

256.  How  much  copper  and  nitric  acid  would  be  re- 
quired in  order  to  prepare  100  1.  of  nitric  oxide  ? 

257.  What   volume   of   oxygen   at    + 120°    C.    and 
743   mm.   can   be   obtained   by  treating   an  excess   of 
+  KMnO4  with  a  1.  of  sulphuric  acid  possessing  a  density 
of  1.84  at  0°C.? 

258.  If  3.5  1.  of  gaseous  hydrofluoric  acid  at  +  10°  C. 
and  765  mm.  were  obtained  by  heating  fluorspar  with 
oil  of  vitriol,  what  weight  of  fluorspar  was  used? 

259.  What  volume  of  oxygen  would  be  required  to  con- 
vert 201  g.  of  phosphorus  into  (a)  P2O3  and  (6)  P2O5? 


104     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

260.  If  150  g.  of  iodine  are  heated  with  red  phos- 
phorus and  water,  what  volume  of  hydriodic  acid  will 
be  produced? 

261.  What  volume  of  sulphuretted  hydrogen  is  re- 
quired  for   the   complete   precipitation   of   a   solution 
containing  5  g.  of  As2O3? 

262.  If  20  g.    of  nitrogen  are  carried  through  the 
following   series  of   reactions,   calculate    the  resulting 
volume  of  nitrous  oxide  at  standard  conditions  : 


3Mg4-N2  = 
Mg3N2  +  6  H20  =  3  Mg(OH)2  +  2  NH3 


NH4N03  =  N20  +  2  H20. 

263.  What   weight   and  what  volume  of   hydrogen 
will  be  evolved  by  the  action  of  15  g.   of  sodium  on 
water  ?     What  weight  of  sodium  hydrate  will  be  pro- 
duced? 

264.  What    volume    of    sulphuretted    hydrogen    at 
+  13°  C.  and  700  mm.  would  be  produced  by  boiling 
15  g.   of  antimony  sulphide  with  strong  hydrochloric 
acid? 

265.  A  piece  of   pure  carbon  weighing   12.5  g.   is 
lighted  and    plunged   into  a  jar  containing   16   g.    of 
oxygen  ;    how  much  carbon,  if  any,   will  remain  un- 
burned  ? 

266.  What  volume  of  hydrogen  at  —  5°  C.  and  770 
mm.   pressure  would  be  evolved  by  dissolving  15  g. 
of  pure  magnesium  in  hydrochloric  acid? 

267.  Calculate    the    volume    of    carbon    dioxide    at 
+  22°  C.  and   740  mm.  that  will  be  liberated  by  the 
action  of  acid  upon  200  g.  of  calcium  carbonate. 


VOLUMES  FROM  EQUATIONS  105 

268.  What  weight  of  magnesium   will  be  required 
for  the  liberation  of  500  cc.  of  hydrogen  at  +  20°  C. 
and  740  mm.  when  acted  upon  by  an  acid? 

269.  What  weight  of  aluminum  will  be  required  for 
the  liberation  of  1420  cc.  of  hydrogen,  measured  over 
water  at  + 18°  C.  and  746.4  mm.,  when  acted  upon  by 
HC1? 

270.  Calculate  the  relative  weights  of  sodium  chlo- 
rate and  potassium  chlorate  necessary  to  give  20  1.  of 
oxygen  at  —  4°  C.  and  770  mm. 

271.  Calculate    the    relative    weights    of   potassium 
chlorate  and   perchlorate   (KC1O4)   necessary  to  give 
320  1.  of  oxygen  at  +  81°  C.  and  692  mm. 

272.  What  volume  of  chlorine,  measured  at  -f-  12°  C. 
and  750  mm.  pressure,  would  be  produced  by  heating 
50  g.  of  common  salt  with  sulphuric  acid  and  manga- 
nese dioxide  ? 

273.  The  iodine  in  600  volumes  of  hydriodic  acid  is 
liberated   in   succession   by  chlorine   and   by  oxygen. 
How  many  volumes  of  chlorine  and  how  many  volumes 
of  oxygen  are  required  ? 

274.  A  piece  of   sodium  was   completely  converted 
into  a  chloride  by  the  absorption  of  200  cc.  of  chlorine. 
What  was  the  weight  of  the  sodium  ? 

275.  How  many  1.  of  sulphuretted  hydrogen  could 
be  obtained  by  the  action  of  sulphuric  acid  upon  329  g. 
of   ferrous   sulphide,    and   what   volume    of   hydrogen 
would  it  contain  ? 

276.  How   many   1.  of    oxygen   would   be    required 
in   order    to   burn    completely   53  1.    of    sulphuretted 
hydrogen  ? 


106     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

277.  How  many  1.  of  sulphur  dioxide  would  be  pro- 
duced by  burning  sulphur  in  158  1.  of  oxygen? 

278.  What    weight    and    what    volume    of    sulphur 
dioxide    ought   to   be    obtained   by  heating    250  g.  of 
copper  with  sulphuric  acid  ? 

279.  If   60  g.   of   mercuric    oxide   are    heated,  what 
volume  of  oxygen  at  -f-  91°  C.  and  380  mm.  is  given 
off? 

280.  What    weight   of   iron   would   be   required   to 
expel  5  1.  of  hydrogen  from  hydrochloric  acid  ? 

281.  A  gas  tank  will  hold  321  g.  of  oxygen.      What 
weight  and  volume  of  nitrogen  and  of  carbon  dioxide 
will  it  hold  ? 


CHAPTER   VIII 

Problems  in   the    Combining  Volumes    of    Gases 
(Gay-Lussac's  Law) 

1.  If  27  g.  of  ethylene  are  completely  burned,  what 
is  the  volume  of  the  products  of  combustion  ? 

2.  If  20  1.  of  hydrogen  and  10  1.  of  chlorine  are  exposed 
to  sunlight,  what  are  the  volumes  of  the  resulting  gases? 

3.  One  1.  of  marsh  gas  is  burned.     Find  weight  and 
volumes  of  oxygen  needed,  and  of  gases  produced. 

4.  If  100  cc.  of  dry  ammonia  gas  are  decomposed 
by  electricity,  what  are  the  weights  and  volumes  of 
gases  formed  ? 

5.  When   16   g.  of   CH4  burn   in   air,  what   is   the 
volume  of  CO2  produced  and  weight  of  water  ? 

6.  If  an  electric  spark  is  passed  through  each  of  the 
following   gaseous   mixtures,    calculate   what   volumes 
result  in  each  case  : 

1st  mixture!  ?  volumes  oxygen 
i  1  volume  hydrogen 

0  -I       .   ,         f  2  volumes  hydrogen 
2d   mixture  1  J 

1  volume 


0  -,       .    .         f  1  volume  hydrogen 
3d   mixture  {  % 

I  2  volumes  chlorine 

A  ,,       .    .         f  1  volume  oxygen 
4th  mixture  \  *  /.c  . 

2  volumes  chlorine 


107 


108     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

7.  If  1  volume  of  carbon  monoxide  is  mixed  with 
1  volume  of  oxygen  and  the  mixture  is  exploded  in  a 
closed  place,  what  will   be  the  volume  of  the  result- 
ing gas  or  mixture  at   the    original    temperature   and 
pressure? 

8.  How  many  1.  of  oxygen  are  required  in  order  to 
burn  completely  4  g.  of  sulphur,  and  how  many  1.  of 
sulphur  dioxide  will  be  formed  ? 

9.  What  weight  of  water  will  be  produced  by  burn- 
ing 5  1.  of  hydrogen  ? 

10.  What  weight  of  HC1  would  result  upon  burning 
1  1.  of  hydrogen  in  chlorine  ? 

11.  How  many  cc.  of   air  are  necessary  to  burn    a 
mixture  containing  375  cc.  of  marsh  gas  and  450  cc. 
of  olefiant  gas  (C2H4),  and  how  much  carbon  dioxide 
and  aqueous  vapor  are  produced  ? 

12.  By  the  combustion  of  1  cc.  of   sulphuric    ether 
having  a  sp.  gr.  of  0.72,  how  many  cc.  of  carbon  dioxide 
and  of  aqueous  vapor  are  produced,   and  how  much 
oxygen  is  consumed  ? 

13.  After    liberating,    by    chlorine,    the    iodine    in 
265  cc.  of  hydriodic  acid,  there  were  318  cc.  of  a  mix- 
ture of  hydrochloric  acid  and  chlorine.     What  was  the 
volume  of  each  gas  in  the  mixture  ? 

14.  How  many  1.  of  air  (21  %  O)  ought  to  be  mixed 
with  100  volumes  of  "  fire  damp"  to  supply  material  for 
the  complete  combustion  of  this  gas  during  explosion  ? 

15.  If   40    g.  of   ammonia   and   40   g.   of    HBr   are 
brought  together,  what  weight  of  ammonium  bromide 
results  ?     What  is  left  over,  and  what  is  its  volume  at 
+  220°  F.  and  768  mm.? 


COMBINING  VOLUMES  OF  GASES  109 

16.  How  many  1.  of  air  at  4-  20°  C.  and  780  mm.  are 
required  for  the  complete  combustion  of  16  1.  of  me- 
thane ;  of  ethylene  ;  of  acetylene  ;  of  carbon  monoxide  ; 
of  ammonia;  of  hydrogen  sulphide? 

17.  If  1000  g.  of  bromine  are  to  be  united  with  hy- 
drogen, what  volume  of  hydrogen  is  needed  at  +  450°  C. 
and  766  mm.  ?     What  volume  of  products  results? 

18.  If  50  1.  of  hydrogen  and  30  1.  of  chlorine  are 
mixed  and  exploded,  what  volume  of  hydrogen  chloride 
is   produced?     What   gas   and  how  much  remains  in 
excess  ? 

19.  What  volume  of  hydrochloric  acid  would  result 
from  the  complete  combination  of  50  1.  of  chlorine  with 
hydrogen,  the  final  temperature  and  pressure  being  the 
same  as  the  initial? 

20.  What  volume  of  hydrogen  would  combine  with 
20  1.  of  oxygen?     How  many  1.  of  water  vapor  would 
result? 

21.  How  many  1.  of  oxygen  will  combine  with  20  1. 
of  nitric  oxide,  and  what  volume  of  nitrogen  peroxide 
would  be  formed? 

22.  What  volume  of  carbon  dioxide  will  result  from 
the  combustion  of  27.4  1.  of  carbon  monoxide? 

23.  What  volume  of  oxygen  is  necessary  to  com- 
pletely burn  40  1.   of  the  vapor  of  benzene,  and  how 
many  1.  of  carbon  dioxide  and  water  vapor  would  be 
formed  ? 

24.  In  a  eudiometer  88  cc.  of  hydrogen  and  132  cc. 
of  chlorine  are  exploded  by  a  spark ;  what  volume  of 
hydrochloric  acid  is  formed,  and  what  volume  of  uncom- 
bined  gas  will  remain? 


110     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

25.  What  volume  of  oxygen  is  required  to  burn  1  1. 
of  the  vapor  of  alcohol  to  carbon  dioxide  and  water? 

26.  What  volume  of  oxygen  is  required  to  burn  com- 
pletely 175  cc.  of  acetylene  ? 

27.  If  ammonia  and  chlorine  react  to  form  nitrogen 
and  hydrochloric  acid,  what  volume  of  chlorine  is  re- 
quired to  react  completely  with  160  1.  of  ammonia,  and 
what  volumes  of  nitrogen  and  hydrochloric  acid  result? 

28.  31.  of  a  mixture  in  equal  volumes  of  CH4,  C2H4, 
and  CO  are  burned,  the  products  being  H2O  and  CO2. 
How  much  oxygen  is  required  and  how  much  CO2  is 
formed  ? 

29.  If  7  1.  of  hydrogen  are  mixed  with  8  1.  of  oxygen 
and  burned  so  far  as  possible,  what  volume  of  the  prod- 
uct (as   a  vapor)  is   formed  and  what  is  left  uncom- 
bined  ? 

so.    What  volumes  of  gases  will  be  left  if  3  1.  of  CH4 
and  2  1.  of  air  are  caused  to  unite,  so  far  as  possible  ? 

31.  What  volumetric  mixture  of  acetylene   and  air 
would  be  most  dangerously  explosive  ? 

32.  Show  the  relative  volumes  of  the  five  gases  pres- 
ent when  alcohol  vapor  burns  in  air. 

33.  How  many  1.  of  hydrochloric  acid  and  of  oxygen 
can  be  made  by  the  use  of  875  g.  of  water?     How  many 
1.  of  chlorine  are  required  ? 

34.  How  many  1.  of  air  are  necessary  to  burn  150  g. 
of  benzol?     Composition  of  air  is  oxygen  20.96%  and 
nitrogen  79.04%. 

35.  When  30  1.  of  hydrogen  were  mixed  with  18  1. 
of  oxygen  and  chemical  union  was  produced,  how  much 
aqueous  vapor  having  a  temperature  of  +  140°  C.  and 


COMBINING  VOLUMES  OF  GASES  111 

760mm.  was  obtained?  Which  gas  remained  in  excess, 
and  what  was  its  volume  at  the  temperature  and  pres- 
sure given  above  ? 

36.  How  many  1.  of  oxygen  would  be  required  to 
burn  101.  of  H2S? 

37.  How  many  1.  of  oxygen  will  combine  with  10  1. 
of  nitric  oxide,  and  what  volume  of  nitrogen  peroxide 
will  be  formed  ? 

38.  If  nitrogen  and  hydrogen  could  be  made  to  com- 
bine completely,  what  volume  of  each  would  be  required 
to  form  10  1.  of  gaseous  ammonia? 

39.  What   volume   of   hydrogen   and  of  oxygen  at 
-f  100°  C.  would  combine  to  form  1  1.  of  steam? 

40.  If  1000  1.  of  ammonia  gas  are  decomposed,  what 
volume  of  nitrogen  and  of  hydrogen  result  if  measured 
at  -10°C.  and  600mm.? 

41.  If  30  cc.  of  hydrogen  are  mixed  with  40  cc.  of 
air  that  contains  20  %  of  oxygen,  and  the  mixture  is 
ignited,  what  gases  remain  after  explosion  and  what 
is  the  volume  of  each? 

42.  A  mixture  of  10  cc.  of  hydrogen  and  10  cc.  of 
chlorine,  exploded  by  an  electric  spark,  yields  20  cc.  of 
hydrogen  chloride.     Show  how  this  indicates  that  the 
molecule  of  hydrogen  consists  of  at  least  two  atoms. 

43.  If   2   volumes  of  ethylene  weighing  28  g.   are 
burned  in  air,  what  volumes  of  nitrogen  and  of  other 
gases  result? 

44.  After  72  cc.  of  NH3  are  decomposed  by  electri- 
city, 100  cc.  of  oxygen  are  introduced  and  the  mixture 
is   exploded;    what   gases  remain   and   how   much  of 
each  ? 


112     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

45.  One  Kg.  of  carbon  disulphide  is  burned  in  oxygen. 
What  weight  of  oxygen  is  needed,  and  what  is  the  volume 
of  each  of  the  products  formed  at  +  20°  C.  and  760  mm.? 

46.  When  150  cc.  of  oxygen  are  mixed  with  400  cc. 
of  hydrogen  and  the  mixture  is  exploded,  what  volume 
of  steam  is  produced?     Which  gas,  and  how  much  of 
it,  remains  uncombined? 

47.  If  50  cc.  of  hydrogen  are  exploded  with  75  cc.  of 
oxygen,  what  is  the  total  volume  of  the  gases  after  the 
explosion,  measured  at  -f  150°  C.  and  760mm.  pressure? 

48.  When  40  1.  of  CO  are  burned,  what  is  the  volume 
of  CO2  produced? 

49.  What  volumes  of  the  components  would  yield 
100  g.  of  nitrogen  tetroxide  ? 

50.  If  500  cc.  of  oxygen  are  exploded  with  250  cc. 
of  hydrogen,  what  gas,  if  any,  will  remain  and  how  much 
of  it? 

51.  How  much  oxygen  will  be  required  for  the  com- 
plete  combustion  of  10  g.    of  stibine  and  arsine,  re- 
spectively ? 

52.  How  many  1.  of  oxygen  are  contained  in  3  1.  of 
nitrogen  tetroxide? 

53.  If  20  g.  of  MnO2  are  boiled  with  an  excess  of 
hydrochloric    acid  until  all  the  MnO2  is  decomposed, 
and   the  resultant  chlorine  is  united  with  hydrogen, 
what  volume  of  H  is  needed,  and  what  volume  of  HC1 
results  if  both  are  measured  at  +  45°  C.  and  746  mm.  ? 

54.  What  volume  of  oxygen  is  required  for  the  com- 
bustion of  575  cc.  of  AsH3? 

55.  How  many  cc.  of  hydrogen  and  nitrogen  are  con- 
tained in  a  1.  of  ammonia  gas  ? 


COMBINING   VOLUMES  OF  GASES  113 

56.  If  100  volumes  of  air  containing  21  volumes  of 
oxygen  are  mixed  with  70  volumes  of  hydrogen,  and  an 
electric  spark  is  passed  through  the  mixture,  what  will 
be  the  volume  of  the  gas  remaining  and  of  what  will  it 
consist  ? 

57.  If  50  cc.  of  hydrogen  are  exploded  with  45  cc.  of 
oxygen,  what  is  the  total  volume  of  the  gases  after  the 
explosion,  measured  at  -f-  150°  C.  and  760  mm.  pressure? 

58.  How  many   cc.    of    hydrogen  and   nitrogen  are 
contained  in  1  m.3  of  ammonia  gas? 

59.  How  many  1.  of  hydrogen  can  be  obtained  from 
61.  of  HC1? 

60.  One  ft.3  of  hydriodic  acid  is  decomposed  by  an 
excess   of  bromine.      How  many   ft.3  of   hydrobrornic 
acid  are  formed? 

61.  What  volume  of  oxygen  is  required  for  the  com- 
plete combustion  of  101  g.  of  SbH3? 

62.  If  50  cc.  of  air  are  mixed  with  25  cc.  of  hydro- 
gen and  exploded  in  a  eudiometer,  what  volume  will 
the  remaining  gas  occupy  and  of  what  will  it  consist? 

63.  What  weight  of  oxygen  is  required  for  the  com- 
plete combustion  of  24  1.    of  phosphine,  measured  at 
+  15°  C.  and  740  mm.  pressure? 

64.  An  unknown  volume  of  hydrogen  sulphide  re- 
quired 157  cc.  of  oxygen  for  complete  decomposition. 
What  was  the  volume  of  the  hydrogen  sulphide? 

65.  A  mixture  of  300  cc.  of  methane  and  150  cc.  of 
oxygen  was  exploded.      What  was  the  volume  of  the 
product  after  the  removal  of  aqueous  vapor  (by  absorp- 
tion), temperature  being  +  100°  C.  and  pressure  760mm. 
constant  throughout? 


114     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

66.  A  mixture  of  250  cc.   of  carbon  monoxide  and 
120  cc.  of  oxygen  was  exploded.     Calculate  the  volume 
of  gaseous  product. 

67.  A  mixture  of  420  cc.  of  hydrogen  and  180  cc.  of 
oxygen  was  exploded.     What  was  the  volume  of  prod- 
uct after  the  removal  of  aqueous  vapor  (by  absorption 
with  phosphorus  pentoxide),  temperature  being  -f  100° 
C.  and  pressure  of  760mm.? 

68.  If  17  1.  of  NH3  are  decomposed,  how  many  1. 
will  there  be  of  resultant  gases  ? 

69.  A  mixture  of   200  cc.  of  carbon  monoxide  and 
300  cc.   of  oxygen  was  exploded  over  mercury.     Cal- 
culate the  volume  of  product,  at  +  27°  C.  and  pressure 
of  740  mm.  constant  throughout. 

70.  A  mixture  of  oxygen  and  hydrogen  measuring 
250  cc.  was  exploded.     The  volume  of  product  meas- 
ured 76.47  cc.,  at  +17°  C.  and  pressure  of  754.4  mm. 
Calculate  the  volumes  of  hydrogen  and  oxygen. 

71.  A  mixture  of  320  cc.   of  carbon  monoxide  and 
1800    cc.    of    oxygen    was    exploded.       Calculate    the 
volume  of   gaseous  product   after  the  removal  of  the 
carbon  dioxide  (absorption  by  lime). 

72.  A  mixture  of  80  cc.  of  methane  and  200  cc.  of 
oxygen   was   exploded   over   mercury.     Calculate   the 
volume  of  product,  at  temperature   of   +  20°  C.   and 
barometric  pressure  of  757.4  mm.   constant. 

73.  A  mixture  of  490  cc.  of  hydrogen  and  1300  cc. 
of   oxygen   was   exploded.    .  Calculate   the   volume    of 
product,    at    temperature    of    -}-  25°    C.    and    pressure 
753.6  mm.  constant. 


i 


COMBINING   VOLUMES  OF  GASES  115 

74.  When  250  cc.  of  dry  air  were  mixed  with  150  cc. 
of  hydrogen  and  exploded,  the  volume  of  product  was 
350  cc.     Calculate   the  percentage   of   oxygen  in   the 
sample  of  air.     Temperature  of  -f  100°  C.  and  atmos- 
pheric pressure  remained  constant. 

75.  A  mixture  of  hydrogen  sulphide  with  an  excess 
of  oxygen  measured  350  cc.  at  + 160°  C.  and  750  mm. 
pressure.  \   After  explosion  (with  complete  combustion), 
the    volume   of   dry  gaseous   product  read  260  cc.  at 
these  same  conditions.     Calculate  the  volume  of  hydro- 
gen sulphide  in  the  mixture. 

76.  Find  the  proportions  by  weight  and  by  volume 
in  which  ethane  will  combine  with  oxygen. 

77.  A  volume  of  nitric  oxide,  measuring  400  cc.,  was 
required   for   the    combustion  of  a  definite  weight  of 
phosphorus.     What  volume  of  nitrogen  remained  free? 

78.  What  volume  of  water  gas  is  theoretically  possible 
from  the  action  of  1  1.  of  steam  upon  heated  coke  ? 

79.  In    the   decomposition  of  methane  by  chlorine, 
what  volume  of  hydrogen  chloride  corresponds  to  1  vol- 
ume of  methane  ? 

80.  A  mixture  of  400  cc.  of  methane  and  1000  cc. 
of  chlorine  was   exploded.     Calculate    the   volume   of 
gaseous  product. 

81.  How  many  1.  of  air  are  required  for  the  com- 
plete combustion  of  10  1.  of  (ft)  marsh  gas ;   (6)  olefiant 
gas ;  (c)  acetylene  ? 

82.  If  5  1.  of  chlorine  are  mixed  with  5  1.  of  carbon 
monoxide,  what  volume  of  phosgene  gas  is  produced, 
and  how  much  hydrochloric  acid  and   carbon  dioxide 
would  be  produced  by  the  decomposition  of  this  gas 
with  water  ? 


116     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

83.  If   5   1.   of  carbon  monoxide  are    burned,  what 
volume  of  oxygen  will  be  used,  and  what  volume  of 
carbon  dioxide  will  be  formed  ? 

84.  If  an  electric  spark  is  passed  through  a  mixture 
of   5   volumes  of  carbon  monoxide  and  3  volumes  of 
oxygen,  what  diminution  in  bulk  will  be  observed  ? 

85.  If  50  cc.  of  carbon  monoxide   are   mixed   with 
20    cc.    of   oxygen    and    exploded,    and   the    resulting 
mixture  is  then  shaken  up  with  sodium  hydrate,  what 
volume  of  gas  will  remain  and  what  gas  will  it  be  ? 

86.  Carbon   is   burned   in    220   1.  of  oxygen;  what 
volume  of  carbon  dioxide  will  be  formed  ? 

87.  If  50  cc.   of  nitrous  oxide  are  decomposed  into 
nitrogen   and   oxygen,  how  many  cc.  of  each  will  be 
formed  ? 

88.  A  mixture  of  acetylene  with  an  excess  of  oxygen 
measured  350  cc.   at  +  25°  C.  and  745  mm.  pressure. 
After  explosion  the  volume  of  dry  gaseous  product  read 
275  cc.  under  the  same  conditions.    Calculate  the  volume 
of  acetylene  in  the  mixture. 

89.  A  mixture  of  acetylene  with  an  excess  of  oxygen 
measured  240  cc.  at  +  24°  C.  and  752.4  mm.  pressure. 
After  explosion  the  volume  of  product  read  221.8  cc. 
at    -f  28°  C.  and  750.1  mm.  pressure.     Calculate  the 
volume  of  acetylene  in  the  mixture. 

90.  If  600  volumes  of  carbon  monoxide  are  mixed 
with  600  volumes  of  oxygen,  an  electric  spark  is  passed 
through  the  mixture,  and  then   a   solution  of  caustic 
potash    is    added,    what    volume  of    gas    will   be  ab- 
sorbed and  of  what  will  the  residue,  if  there  is  any, 
consist? 


COMBINING  VOLUMES  OF  GASES  117 

91.  How  many  volumes  of  oxygen  are  required  for 
the  complete  combustion  of  1  1.  of  each  of  the  following  : 
(a)  CO;  (6)  CH4;  <»  C2H4;  (d)  C2H2  ;  <»  H2S  ; 


92.  If  500  cc.  of  hydrogen  at  +  39°  C.  are  exploded 
with  500  cc.  of  oxygen  under  a  pressure  of  332.5  mm., 
what  volume  of  which  gas  is  left  ? 

93.  How  many  1.  of  oxygen  will  be  required  to  burn 
50  1.  of  C2H4  and  how  many  of  CO2  will  form  ? 

94.  If  10  ft.3  of  H2S  are  burned,  what  volume  of  each 
product  will  be  formed  ? 

95.  I  have  5500  cc.  of  CO2  formed  by  the  combustion 
of  CO  in  air.     How  much  air  was  required  and  how 
much  CO  ? 

96.  State  the  volume  of  the  products  resulting  from 
the  combustion  of  2.5  1.  of  carbon  disulphide  gas. 

97.  What  volume  of  products  results  from  the  de- 
composition of  100  1.  of  ammonia  ? 

98.  One  million  molecules    of    hydrogen  will  unite 
with  how  many  molecules  of  oxygen  to  form  how  many 
molecules  of  water  ?    What  will  be  the  relative  weights 
of  hydrogen  and  water  ? 

99.  A  mixture  of  10  cc.  of  chlorine  and  10  cc.  of 
hydrogen,  exploded  by  an  electric  spark,  yields  20  cc. 
of  hydrogen  chloride.      Show  how  this  indicates  that 
the  molecule  of  hydrogen  consists  of  at  least  2  atoms. 


CHAPTER   IX 

Calculation  of  Formulas 

1.  A  compound  has  the  following  percentage  com- 
position:    carbon,   37.61%  ;    hydrogen,  12.53%  ;    oxy- 
gen, 49.86%.      One  1.  of  its  vapor  weighs  1.4339  g., 
What  is  its  formula  ? 

2.  A   gas  has   the   following   composition  :    carbon, 
27.39%;  oxygen,  72.60%.     Its  density  (air)  is  1.52. 
What  is  its  formula  ? 

3.  What    is   the   simplest    formula   of    a    substance 
which    consists    of    oxygen,   88.83%,    and    hydrogen, 
H.11%? 

4.  Calculate  the  simplest  formula  of  mercuric  oxide, 
which  contains  92.59  %  of  mercury  and  7.41  %  of  oxygen. 

5.  What    is    the   simplest   formula    of    a   substance 
consisting  of  calcium,  29.49%  ;   sulphur,  23.59%  ;  and 
oxygen,  46.92%? 

6.  The  percentage  composition  of  a  mineral  is  found 
to  be:  calcium,  40.12%  ;    carbon,  12.04%;  and  oxy- 
gen, 47.84%.     What  is  its  simplest  formula? 

7.  Acetic  acid  consists  of  carbon,  40  %  ;  hydrogen, 
6.67%;    and  oxygen,  53.33%.       Its  vapor  density  is 
30.     What  is  its  molecular  formula  ? 

8.  What  is  the  molecular  formula  of  the  gas  having 
the  composition  :  nitrogen,  30.43  %  :  oxygen,  69.57  %  ? 
The  weight  of  1  1.  is  2.061  g. 

118 


CALCULATION  OF   FORMULAS  119 

9.  What  is  the  molecular  formula  of  the  gas  having 
the  density  197  and  the  composition:  iodine,  96.70%; 
carbon,  3.05%  ;  hydrogen,  0.25%? 

10.  In  100  parts  of  a  compound  of  manganese  and 
oxygen  there  are  63.22  parts  of  manganese  and  36.78 
parts  of  oxygen.     What  is  the  simplest  formula  possi- 
ble? 

11.  Calculate  the  formulas  of  the  following  : 

Ba  =  58.80  K  =  31.91  Ca  =  40.00  Ag  =  75.27 
8  =  13.75  01  =  28.94  0  =  12.00  01  =  24.73 
O  =  27.45  O  =  39.15  O  =  48.00 


12. 

K  =  38.68 

N  =  13.89 

Mg  =  21.65 
P  =  27.92 

K  =  16.00 
Pt  =  40.41 

Na=18.54 
8  =  25.84 

0=47.43 

O  =  50.43 

01  =  43.59 

H=    0.81 

0  =  25.79 

H2O  =  29.02 

13. 

Na  =  18.54  CaO=    9.20  Fe  =  72.41 

8  =  25. 84  A12O3  =  16.85  O  =  27. 59 

H=    4.03  Si02  =  59.29  Mn  =  71.69 

O  =  51.59  H2O  =  14.66  O  =  28.31 

14. 

Cu  =  34.46    CaO  =  43.45  Ag  =  53.15       Lithia  =    6.43 

Fe  =  30.59  A12O3  =  17.68  Cu  =  31.08  Alumina  =  29.26 

8  =  34.95    SiO2  =  38.87     8  =  15.77        Silica  =  64.31 


15. 

Pb  =  76.36 

0  =  21.03 

0  =  52.17 

K  =  42.41 

P=    6.86 

H=    2.63 

H  =  13.04 

Fe  =  15.22 

01=    2.62 

K  =  34.27 

O  =  34.79 

0  =  19.56 

O  =  14.16 

O  =  14.03 

N  =  22.81 

8  =  28.04 

120     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

16. 

0  =  90.57        0  =  89.55        0  =  79.73  Si  =  19.50 

H  =  9.43         H  =  10.45        H=    6.32  0  =  66.62 

N=  13.95  H  =  13.88 

17. 

0  =  75.46          H  =  6.59         N  =  8.38         O  =  9.57 

18.  Find  the  formula  of  that  nitrate  which  gave,  by 
analysis,  62.45%  lead,    8.68%  nitrogen,  and   28.85% 
oxygen. 

19.  Derive  the  formula  of  that  substance  which  gave, 
by  analysis,   52.02%    carbon,    13.20%   hydrogen,   and 
34.68%  oxygen. 

20.  What  is  the  formula  of  that  acetate  which  gave, 
by  analysis,  63.61  %  lead,  14.62  %  carbon,  1.98  %  hydro- 
gen, and  19.79%  oxygen? 

21.  An  oxide  of  iron  gave,  by  analysis,  69.80  %  iron  ; 
what  is  the  formula? 

22.  An   oxide    of   barium   gave,   by   analysis,    81  % 
barium  ;  what  is  the  formula? 

23.  The  vapor  density  of  a  gas  is  13.91.     The  analy- 
sis gives  the  following    composition:     0  =  85.62    and 
H  =  14.38.     What  is  the  formula?     Find  the  weight 
of  11. 

24.  Derive  the  formula  of  the  oxide  produced  when 
6.87  g.  of  barium  unite  with  1.6  g.  of  oxygen. 

25.  Find    the    formula  of  the   oxide  formed  in  the 
combustion  of  2.61  g.  of  aluminum  with  oxygen  to  a 
final  weight  of  5.01  g. 

26.  What  is  the  formula  of  the  oxide  produced  by  the 
combustion  of  43.45  g.  of  lead  with  4.48  g.  of  oxygen? 


CALCULATION   OF  FORMULAS  121 

27.  Derive  the  formula  of  the  oxide  produced  by  the 
burning  of  2.5  g.  of  phosphorus  in  oxygen  to  a  final 
weight  of  5.7  g. 

28.  Calculate  the  formulas  of : 

00  (*) 

N  =  22.05  Si02  =  23.53 

C  =  14.18  CaO=    1.90 

O  =  56.68  A12O3  =  37.72 

H=    7.09  Water  =  36.85 

29.  What  will  be  the  formula  of  a  hydrocarbon  that 
contains  twice  as  many  hydrogen  atoms  as  carbon,  and 
the  vapor  of  which  has  a  density  of  1.947? 

30.  Find  the  simplest  formula  for  acid  potassic  car- 
bonate, its   percentage    composition  being :    hydrogen, 
1.00;  potassium,  39.06;  carbon,  11.99;  oxygen,  47.95. 

31.  In  100  parts  of  crystallized  ferrous  sulphate  there 
are  20.15  parts  of  iron,  11.51  parts  of  sulphur,  23.02 
parts  of  oxygen,  and  45.32  parts  of  water;  what  is  its 
simplest  formula? 

32.  What  is  the  simplest    formula   of  morphia,  its 
percentage  composition  being:  carbon,  71.58;  hydrogen, 
6.66;  nitrogen,  4.91;  oxygen,  16.85? 

33.  Derive  the  formula  of  crystallized  sodium  sul- 
phate,  8.16  g.  of  which   lost   4.51  g.   of  water  upon 
dehydration. 

34.  Find  the  formula  of  crystallized  copper  sulphate, 
7.84  g.  of  which  lost  2.79  g.  of  water  upon  heating. 

35.  Calculate  the  formula  of  crystallized  aluminum 
sulphate,  9.54  g.  of  which  lost  4.61.  g.  of  water  upon 
heating. 


122     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

36.  Work  out  the  formula  of  aluminum  hydroxide, 
4.75  g.  of  which  lost  1.64  g.  of  water  and  left  a  residue 
of  AL03. 

L       6 

Deduce  the  formulas  of  the  following  substances : 

37.  Magnesium,    9.76;     sulphur,     13.01;     oxygen, 
26.01;    water,  51.22. 

38.  Zinc,   22.70;    sulphur,    11.15;    oxygen,    22.28; 
water,  43.87. 

39.  Sodium,  32.79;  aluminum,  13.02;  fluorine,  54.19. 

40.  Aluminum,  16 ;  sulphur,  28 ;  oxygen,  56. 

41.  Copper,  57.46;    carbon,  5.43;    hydrogen,  0.91; 
oxygen,  36.20. 

42.  Hydrogen,  3.18;  oxygen,  33.88;  nitrogen,  14.84; 
sulphur,  16.95;  nickel,  31.15. 

43.  Carbon,  19.04;  hydrogen,  4.76 ;  sulphur,  25.40; 
oxygen,  50.80. 

44.  Carbon,  46.66;  hydrogen,  4.26;  nitrogen,  5.20; 
oxygen,  5.92;  platinum,  18.26 ;  chlorine,  19.70. 

45.  Calculate  the  formula  of  the  nitrate,  19.7  g.  of 
which  were  prepared  from  10.4  g.  of  bismuth. 

46.  Find  the  formula  of  that  chlorate,  4.165  g.  of 
which  lost  1.3  g.  of  oxygen  upon  heating  and  gave  a 
residue  of  barium  chloride. 

47.  What  is  the  formula  of  mercuric  cyanide,  5.4  g. 
of  which  lost  1.1  g.  of  cyanogen  upon  heating? 

48.  Derive  the  formula  of  the  double  salt  of  ammo- 
nium sulphate  and  copper  sulphate,  4.12  g.  of  which 
lost  1.81  g.  of  ammonium  sulphate  upon  heating. 

49.  The  vapor  density  of  steam  is  9.     The  percent- 
age composition  of  water  is  :  hydrogen,  11.11 ;  oxygen, 
88.89.     What  is  the  formula  of  water  ? 


CALCULATION  OF  FORMULAS  123 

50.  The  vapor  density  of  alcohol  vapor  is  23.     In 
100  parts  there  are  52.18  parts  of  carbon,  13.04  parts 
of  hydrogen,  and  34.78  parts  of  oxygen.     What  is  the 
formula  of  alcohol  ? 

51.  The  vapor  density  of  the  vapor  of  ethylene  chloride 
is  49.5,  and  its  percentage  composition  is:  carbon,  24.24; 
hydrogen,  4.04  ;  chlorine,  71.72.     What  is  its  formula? 

52.  The  vapor  density  of  a  certain  gas  is  13.91,  or  the 
weight  of  a  1.  of  this  gas  at  0°  C.  and  760  mm.  pressure 
is  1.26  g.    (Use  only  one  of  these  weight  relations.)    The 
analysis  of  this  gas  gave  the   following  percentages: 
carbon,  85.62;  hydrogen,  14.38.    What  is  the  formula? 

53.  Analysis  of  a  compound  gave :    lead,  68. 30  %  '•> 
sulphur,  10.55%;  oxygen,  21.15%.     Calculate  the  em- 
pirical formula. 

54.  Calculate  the  empirical  formulas  from  the  follow- 
ing analytical  results  :    potassium,  52.45  %  ;    chlorine, 
47.55  %  -    Arsenic,  41.32  %  ;  chlorine,  58.66  % .    Sodium, 
32.43%;     hydrogen,     0.71%;     phosphorus,    21.82%; 
oxygen,  45.04  %.     Potassium,  35.56  %  ;  iron,  17.00  %  ; 
cyanogen,  47.44  % .     Magnesium,  21. 82  % ;  phosphorus, 
27.86%  ;  oxygen,  50.32%. 

55.  Aldehyde    has    the    following  composition :     C, 
54.67%;    H,   9.11%;    and  O,  36.22%.     The  density 
(air)  of  its  vapor  is  1.526.     What  is  its  formula? 

56.  Butyric  acid  has  the  same  percentage  composi- 
tion as  an  aldehyde,  but  the  density  (air)  of  its  vapor 
is  3.052.     What  is  its  formula  ? 

57.  Analysis  of  a  compound  gives  26.67  %  C,  2.22  % 
H,  and  71.11  %  O  ;  what  is  its  simplest  formula  ?    If  that 
is  the  correct  one,  what  should  be  the  vapor  density  of 
the  gas  ? 


124     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

58.  A  compound  consists  of  5.88  %  H  and  94.12  %  O  ; 
find  the  smallest  formula  that  can  apply  to  it. 

59.  An  ore  of  iron  analyzes  70  %  Fe  and  30  %   O  : 
what  formula  should  it  have  ? 

60.  Zinc  is  obtained  from  its  sulphide,  a  specimen  of 
which  contains  67.01%  Zn  and  32.99%  S.     Ascertain 
the  formula  of  zinc  sulphide. 

61.  Find  the  formula  of  a  hydrocarbon  that  contains 
an  equal  number  of  hydrogen  and  carbon  atoms,  and 
the  vapor  of  which  has  a  density  (air)  of  0.9. 

62.  Formic  acid   has  the  composition:  C,  26.21%; 
O,  69.43%  ;  and  H,  4.36%.     The  density  (air)  of  its 
vapor  is  the  same  as  that  of  alcohol.    Find  the  formula. 

63.  Find  the  formulas  of  the  following  two  substances : 

00  (0 

Bi  =  42.99  K=    8.24 

O  =  29.74  Al=    5.69 

N=    8.67  8  =  13.50 

Water  =  18.60  O  =  27.01 

Water  =  45. 56 

64.  Oxalic  acid  consists  of  C,  26.79%;   H,  2.23%; 
and  O,  70.98  %.     Find  the  formula. 

65.  Alcohol  is  C,  52.28;    O,  34.64;  and  H,  13.08. 
Calculate  the  formula. 

66.  Deduce  the  formulas  of  the  following : 

00  (*) 

Fe  =  20.15  K=    7.77 

8  =  11.51  Mn  =  10.95 

O  =  24.02  8  =  12.75 

Water  =  44. 32  O  =  25.48 

Water  =  43. 05 


CALCULATION  OF  FORMULAS  125 

67.  Red  lead  consists  of  Pb,  90.65  %  ;  and  O,  9.35  %. 
What  is  the  formula  ? 

68.  The  sp.gr.  of  mercurous  chloride  is  7.     It  con- 
tains 84.92  %  of  Hg  and  15.08  %  of  chlorine.     To  what 
formula  would  this  correspond  ? 

69.  Calculate  the  formula  of  the  following : 

Na  =  14.41    Sb  =  25.05  8  =  26.72  Water  =  33.82 

70.  Calculate  the  formulas  from  the  following   per 
cents:    calcium,    38.72;    phosphorus,    20.00;    oxygen, 
41.28. 

71.  Potassium,    28.73;     hydrogen,    0.73;     sulphur, 
23.52;  oxygen,  47.02. 

72.  Potassium,    45.95;     nitrogen,    16.45;     oxygen, 
37.60. 

73.  Aluminum,  16 ;  sulphur,  28 ;  oxygen,  56. 

74.  Carbon,  85.71;  hydrogen,  14.29. 

75.  Carbon,  92.3;  hydrogen,  7.7. 

76.  One     volume     of     a    gaseous    hydrocarbon    at 
-f  100°  C.  yields  on  combustion  double  its  volume  of 
CO2  and  3  times  its  volume  of  steam  at  the  same  tem- 
perature.    Find  the  formula  of  the  gas. 

77.  A   compound   has   the    following    composition : 
phosphorus,      20.22%;     oxygen,     10.43%;     chlorine, 
69.35%.     The   density    (air)    of   its  vapor   is   5.295. 
What  is  its  formula? 

78.  If  an  iron  ammonium  sulphate  contains  \  of  its 
weight  in  iron,  find  the  formula. 

79.  A    compound    has   the   following    composition : 
phosphorus,  22.58%  ;  chlorine,  77.42%.     One  1.  of  the 
vapor  weighs  6.13  g.     Calculate  the  formula. 


126     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

80.  Calculate   the   formulas  of   the    substances  pos- 
sessing the  following  percentage  compositions : 
Magnesium  =  25.57  Sodium  =32.43  Potassium  =  26.585 

Chlorine  =  74.43  Sulphur  =  22.55  Chromium  =  35.390 
Oxygen  =  45.02       Oxygen  =  38.025 

81.  Find  the  formula  when  Zn  =  22.67;   S  =  11.15; 
O  =  22.29;  and  water  =  43. 89. 

82.  Calculate      the      formula     when      Zn  =  54.14; 
Si  =  11.67  ;   O  =  26.67  ;  and  water  =  7.52. 

83.  Assign  formulas  to  the  following  : 

00  0) 

CO  =  22. 74  A12O3  =  16.86 

N  =  26.96  CaO=    9.20 

Cl  =  41.05  SiO2  =  59.28 

H=    5.78  Water  =  14. 66 

Water  =    3.47 

84.  Calculate  the  formulas  from  the  following  per 
cents:     carbon,      19.04;     hydrogen,     4.76;     sulphur, 
25.40;  oxygen,  50.80. 

85.  Carbon,  74.07;  hydrogen,  8.64;  nitrogen,  17.29. 

86.  Carbon,  46.66 ;  hydrogen,   4.26;  nitrogen,  5.20; 
oxygen,  5.92;  platinum,  18.26;  chlorine,  19.70. 

87.  Lime,    28.4;     magnesia,    12.3;    iron    monoxide, 
12.3;  manganese  monoxide,  1.9;  carbon  dioxide,  44.4. 

88.  A  mineral  gave  the  following  numbers  on  analysis : 
SiO2,  46.96;  MgO,  31.26;  H2O,  21.22.     Calculate  its 
formula. 

89.  A  specimen  of  cobalt  bloom  was  found  to  have 
the  following  composition:  As2O5,  38.43;  CoO,  36.52 ; 
FeO,  1.01;  H2O,  24.14.     Determine  its  formula. 


CALCULATION   OF   FORMULAS  127 

90.  One  hundred  OG.  of  ammonia  gas  are  completely 
decomposed  by   a   series   of   electric   sparks,   yielding 
200  cc.  of  mixed  hydrogen  and  nitrogen.     An  excess 
of  oxygen  is  next  added,  when  the  volume  of  mixed 
gases  is  found  to  amount  to  290  cc.     The  mixture  is 
now  exploded,  when  65  cc.  of  gas  remain.     Show  from 
these  data  that  the  formula  for  ammonia  is  NH3. 

91.  Ca  =  40;      C  =  12;       O  =  48.       Calculate     the 
simplest   formula.     Find   the   percentage    composition 
of  C  in  this  formula  to  see  if  your  answer  is  correct. 

92.  Calculate  the  molecular  formula  of  a  substance 
having   the    following    composition:     carbon,    74.1%; 
hydrogen,  8.6  %  I  nitrogen,  17.3  %.     The  vapor  density 
is  81. 

93.  C  =  10.04%;    H  =  0.83%;    Cl  =  89.13%;    and 
the  vapor  density  is  59.75.     Find  the  formula. 

94.  On  analysis,  18  g.   of  a  compound  of  iron  and 
sulphur  yielded   8.4  g.  of  iron  and  9.6  g.  of  sulphur; 
what  is  its  simplest  formula  ? 

95.  On  analysis,  48  g.  of  a  compound  yielded  37.21  g. 
of  lead,  2.16  g.  of  carbon,  and  8.63  g.  of  oxygen;  what 
is  its  simplest  formula? 

96.  What  is  the    simplest   formula   of  a  substance, 
27  g.  of  which,  on  analysis,  yielded  2.64  g.  of  magne- 
sium,   3.51    g.    of    sulphur,    7.02   g.    of    oxygen,    and 
13.83  g.  of  water? 

97.  A  compound  of  arsenic  and  oxygen  is  composed  of 
75+%As,  24+%  O;  what  is  its  smallest  formula?     Its 
vapor  density  being  198,  what  should  be  its  true  formula? 

98.  A  compound  of  hydrogen  and  carbon  has  92.3% 
C  and  7.7  %  H.     Find  its  smallest  formula.     The  density 
being  13,  what  is  the  proper  formula? 


128     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

99.  An  analysis  of  a  salt  gave  the  following  per- 
centage numbers:  S,  22.53;  Na,  32.39;  O,  45.08. 
What  is  its  empirical  formula? 

100.  A  salt  on  analysis  gives  the  following  percent- 
age numbers:  N,  9.09;  O,  20.77;  Ag,  70.13.     Calcu- 
late the  simplest  formula  for  this  body. 

101.  Calculate  the  formula  for  a  body  which  has  the 
following  percentage  composition:    oxygen,  38.1;   hy- 
drogen, 0.8;  phosphorus,  24.6  ;  sodium,  36.5. 

102.  Calculate  the  formula  of  a  body  which  has  the 
following  percentage  composition:    magnesium,    3.98; 
calcium,     13.28;     potassium,    12.99;    sulphuric     acid 
(SO4),  63.77;  water,  5.98. 

103.  Find  the  formula  of  the  following :  O,  48  %  ; 
S,  24%;  andFe,  28%. 

104.  A   substance  contains   carbon,   20  % ;    oxygen, 
26.6%;  and  sulphur,  53.3%.     Find  its  formula. 

105.  Find  the  formulas  of  the  following  minerals : 

00  (ft) 

SiO2=  65.69  N2O  =    4.21 

A12O3  =  17.97  CaO  =  12.93 

CaO=    1.34  A12O3=  30.68 

N20=    1.01  Si02  =  39.99 

K20  =  13.99  H20  =  12.19 

106.  Calculate  the  formulas  : 

00  (ft) 

A12O3  =  58.66  SiO2  =  47.24 

SiO2  =  34.20  MnO2  =  31.50 

F=    7.14  Water  =21. 26 


CHAPTER  X 

Atomic  and  Molecular  Weight  Calculations 

1.  Ten  1.  of  a  gas  weigh  17.92  g. ;  find  its  molecular 
weight. 

2.  The  sp.  gr.  of  hydrogen  iodide  is  4.4;  calculate 
its  molecular  weight. 

3.  Find  the  molecular  weight  of  the  gas  of  which 
20  g.  occupy  9.9  1.  under  1.5  atmospheres  pressure  at 
+  17°C. 

4.  One  hundred  g.  of  lead  form  146.45  g.  of  lead 
sulphate;  find  the  molecular  weight  of  sulphuric  acid. 

5.  The  vapor  of  a  compound  is  found  to  be  thirty- 
nine  times  as  heavy  as  hydrogen  at  the  same  tempera- 
ture and  pressure.     What  is  the  molecular  weight  of 
the  compound? 

6.  A  1.  of  nitrous  oxide  weighs  1.97  g. ;   find  its 
molecular  weight. 

7.  Find  the  molecular  weight  of  the  gas  the  density 
of  which  is  1.524. 

8.  A   1.   of   ammonia,  under   standard   conditions, 
weighs  0.76  g. ;  find  its  molecular  weight. 

9.  A  1.  of  nitrous  oxide,  under  standard  conditions, 
weighs  1.97  g. ;  find  its  molecular  weight. 

10.    A   1.  of   cyanogen,  under   standard   conditions, 
weighs  2.33  g. ;  find  its  molecular  weight. 

129 


130     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

11.  A  1.  of  ethane,  under  standard  conditions,  weighs 
1.34  g. ;  find  its  molecular  weight. 

12.  Find  the  molecular  weight  of  the  gas  the  density 
of  which  is  1.108. 

13.  A  1.  of  arsine  weighs   3.49  g.  under  standard 
conditions  ;  find  its  molecular  weight. 

14.  Find  the  molecular  weight  of  the  gas  the  density 
of  which  is  0.623. 

15.  Calculate  the  molecular  weights  of  the  following 
gases : 

one  1.  of  ethane  weighs  1.34  g. ; 

one  1.  of  hydrogen  sulphide  weighs  1.52  g.; 

one  1.  of  nitric  oxide  weighs  1.34  g.; 

one  1.  of  phosphine  weighs  1.52  g. ; 

one  1.  of  carbonyl  chloride  weighs  4.42  g. ; 

one  1.  of  SiF4  weighs  4.68  g. ; 

one  1.  of  butane  weighs  2.59  g. 

16.  The  weight  of  3840  cc.  of  a  certain  vapor,  at 
standard  conditions,  is  24  g. ;    what  is  the  molecular 
weight  of  the  substance  ? 

17.  If  3180  cc.  of  a  gas,  measured  at  +  24°  C.  and  750.2 
mm.  pressure,  weighed  6  g.,  what  is  the  molecular  weight? 

18.  The  vapor  density  of  a  gas  is  44 ;   find  its  mo- 
lecular weight,  sp.  gr.,  and  the  weight  of  1  1. 

19.  Calculate  the  molecular  weights  of  the  following 
gases: 

the  density  (referred  to  air)  of  ammonia  is  0.59; 

the  density  (referred  to  air)  of  HF  is  0.69; 

the  density  (referred  to  air)  of  methyl  alcohol  is  1.11 ; 
the  density  (referred  to  air)  of  mercury  vapor  is  6.91; 
the  density  (referred  to  air)  of  HI  is  4.42. 


ATOMIC  AND  MOLECULAR  WEIGHTS          131 

20.  Find    the    molecular    weights    of   the  following 
bodies:  (air  =  l) 
cadmium  at  +  940°  C.,        relative  density  =  3.94 ; 
phosphorus  at  +  500°  C.,     relative  density  =  4.35  ; 
mercury  at  +  446°  C.,         relative  density  =  6.98. 

21.  Determine  the  molecular  weights  of  the  follow- 
ing gases  from  the  data  annexed:  nitrogen;  2  1.  weigh 
2.51  g. 

22.  Carbon  monoxide;  1500  cc.  weigh  1.88  g. 

23.  Carbon  dioxide  ;  500  cc.  weigh  0.98  g. 

24.  One  1.  of  SO2  weighs  2.86  g. ;  what  is  its  molec- 
ular weight? 

25.  The  weight  of  1|  1.  of  CO  is  1.88  g.;  calculate 
the  molecular  weight. 

26.  What  is  the  molecular  weight  of  marsh  gas,  3  1.  of 
which  weigh  2.15  g.? 

27.  Sulphur  dioxide  is  2.22  times  as  heavy  as  air; 
find  its  density  and  molecular  weight. 

28.  If  30  g.  of  a  gas  occupy  52.7  1.  under  0.5  atmos- 
pheric pressure  at  -f  27°  C.,  what  is  the  molecular  weight 
of  the  gas? 

29.  A  quantity  of  gas  measuring  5.4  1.,  when  the 
temperature  is  +  15°  C.  and  pressure  740  mm.,  weighs 
7.6  g. ;  what  is  its  molecular  weight? 

30.  The  vapor  density  of  a  gas  was  31.17  when  its 
temperature  was  + 11°  C.  and  under  a  pressure  of  750 
mm.;  what  is  its  molecular  weight? 

31.  Calculate  the  molecular  weights  of  the  following 
gases  from  their  vapor  densities:    (a)   chlorine,  35.5; 
(5)  hydrochloric  acid,  18.25;    (e)    ammonia,  8.5; 
nitrogen,  14;  (e)  steam,  9. 


132     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

32.  Berzelius    found    that    4.20775   parts  of  MnCl2 
yielded  9.575  parts  of  AgCl ;  what  is  the  atomic  weight 
of  silver? 

33.  By  analysis  we  find  that  for  every  100  parts  of 
silver  bromide  there  are  57.44  parts  of  Ag  and  42.56 
parts  of  Br.     The  atomic  weight  of  Br  =  79.8.     What 
is  the  atomic  weight  of  silver? 

34.  We  find  from  analysis  that  barium  chloride  con- 
tains 65.86%  of  Ba  and  34.14%  of  Cl.     There  are  no 
compounds  of  Ba  the  vapor  density  of  which  has  been 
determined.     The  specific  heat  of  Ba  being  unknown, 
how  would  you  determine  the  atomic  weight  of  Ba? 

35.  Marignac  found  that  3.8844  g.   NaCl  were  re- 
quired for  the  precipitation  of  11.308  g.  of  AgNO3 ; 
find  atomic  weight  of  nitrogen. 

36.  By  heating  15  g.   of  pure  silver  in  a  stream  of 
chlorine,  19.9306  g.   of  silver  chloride  are  produced. 
The  weight  of  the  atoms  of  silver  in  a  molecule  of  silver 
chloride  is  108.     What  is  the  molecular  weight  of  sil- 
ver chloride  and  the  number  of  atoms  of  chloride  in  a 
molecule? 

37.  If  3.17  g.  of  iron  form  4.53  g.  of  Fe2O3,  what  is 
the  atomic  weight  of  iron  ? 

38.  If  8019  cc.   of  a  gas,  measured  over  water  at 
+  20°  C.  and  742.4  mm.  pressure,  weighed  14  g.  when 
deprived  of  aqueous  vapor,  what  is  the  molecular  weight  ? 

39.  If    5647  cc.   of  a  gas,  measured  over  water  at 
+  24°  C.   and  754.2  mm.   pressure,  weighed  6.254  g. 
when  deprived  of  aqueous  vapor,  what  is  its  molecular 
weight  ? 


ATOMIC  AND  MOLECULAR  WEIGHTS  133 

40.  A  compound  of  phosphorus,  oxygen,  and  chlorine 
contained  20.19%  of  phosphorus,  10.43%   of  oxygen, 
and  69. 38% 'of  chlorine.      The  vapor  density  of  the 
compound  as  gas  =  77.95  and  the  specific  heat  of  phos- 
phorus =  0.202.     Find  the  molecular  formula   of   the 
compound  and  the  atomic  weight  of  phosphorus. 

41.  The  sp.  gr.  of  phosphorus  trichloride  is  4.88; 
what  is  its  molecular  weight? 

42.  Sodium    chloride    contains    39.32%    of    sodium 
and  its  molecular  weight  is  58.5.     What  is  the  atomic 
weight  of  sodium,  on  the  supposition  that  there  is  but 
1  atom  of  sodium  in  the  molecule  of  salt  ? 

43.  Berzelius  obtained  17.554  g.  of  PbO  from  16.2956 
g.  of  lead ;  find  the  atomic  weight  of  lead. 

44.  CuO,  when  heated  in  hydrogen,  lost  59.80  g.  of 
oxygen  and  formed  67.3  g.  of  water.     If  O  =  16,  what 
is  the  atomic  weight  of  hydrogen  ? 

45.  Stas  found  that  91.46  g.  of  metallic  silver,  when 
heated  in  a  stream  of  chlorine,  yielded  121.4993  g.  of 
pure  silver  chloride.     Calculate  from  this  the  atomic 
weight  of  chlorine. 

46.  Stas  found,  after  adding  7.25682  g.  of  potassium 
chloride  to  10. 51995  g.  of  silver  dissolved  in  nitric  acid, 
that  0.0194  g.  of  silver  remained  in  solution.    Calculate 
from  these  data  the  atomic  weight  of  potassium. 

47.  Erdmann  and  Marchand  obtained  109.6308  g.  of 
mercury  from  118.3938  g.  of  the  red  oxide.     Calculate 
the  atomic  weight  of  mercury. 

48.  If  0.3697  g.  of  aluminum  liberated  0.04106  g.  of 
hydrogen  on  being  dissolved  in  a  strong  solution  of  so- 
dium hydrate,  what  is  the  atomic  weight  of  aluminum  ? 


134     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

49.  Marignac  found  that  5  g.  of  strontium  chloride, 
containing  6  molecules  of  water  of  hydration,  yielded 
3.442  g.  of  strontium  sulphate.    Calculate  the  equivalent 
of  strontium. 

50.  Pure  carbon  monoxide  was  passed  over  red-hot 
copper  oxide;  the  residual  metal  and  the  carbon  dioxide 
formed  were  weighed;    24.360  g.  of  oxygen  were  lost 
and  67.003  g.  of  carbon  dioxide  were  obtained.     From 
this  calculate  the  atomic  weight  of  carbon. 

51.  One  g.  of  an  element  is  found  to  combine  with 
oxygen  so  as  to  form   2.9  g.   of   oxide;  calculate   its 
equivalent. 

52.  If  0.254  g.  of  a  metal,  when  dissolved  in  hydro- 
chloric acid,  liberated  116  cc.  of  hydrogen,  measured 
at   +  15°  C.  and  725  mm.,  what  is  the  equivalent  of 
the  metal? 

53.  Phosphine  contains  91.17  %  of   phosphorus  and 
8.83  %  of  hydrogen ;  find  the  equivalent  of  phosphorus. 

54.  Three   oxides  of   nitrogen  contain,  respectively, 
63.63%,  46.66%,  and  36.84%   of  nitrogen;    calculate 
the  equivalent  of  nitrogen  in  each  of  them. 

55.  A  bromide  of  antimony  contains  66.66%  of  bro- 
mine.   If  Br  =  80,  calculate  the  equivalent  of  antimony. 

56.  A  1  %  sugar  solution  gives  an  osmotic  pressure 
of  516  mm.  at  -f  15°  C.     What  is  the  molecular  weight 
of  sugar?     Assume  that  the  sp.  gr.  of  the  solution  is  1. 

57.  The  specific  heat  of  an  element  is  -^  ;    and  its 
atomic  weight  is  a  multiple  of  14.     Find  the  atomic 
weight  of  the  element. 

58.  If   200   parts   of   BaCl2   give   224.2   of    BaSO4, 
what  is  the  atomic  weight  of  barium  ? 


ATOMIC  AND  MOLECULAR  WEIGHTS          135 

59.  The  equivalent  of  lead  is  found  to  be  103.5  and 
that  of  platinum  48.6;   determine  the  probable  atomic 
weight  of  both  lead  and  platinum,  specific  heat  of  lead 
being  0.0310  and  of  platinum  0.0324. 

60.  A  1.  of  oxygen  under  standard  conditions  weighs 
1.43  g.     A  1.  of    a   certain  element,  the    molecule  of 
which  contains  2  atoms,  if  vaporized  under  the  same 
conditions,  would  weigh  11.43  g.     What  is  the  atomic 
weight  of  the  element  ? 

61.  When  2.16  g.  of  silver  are  treated  with  chlorine, 
2.87  g.  of  AgCl  are  formed  ;  calculate  the  atomic  weight 
of  silver. 

62.  If  10  g.   of  the  chloride  of  a  certain  univalent 
element  are  found  to  contain  60.6%  of  chlorine,  and 
if  the  atomic  weight  of  chlorine  is  35.5,  what  is  the 
atomic  weight  of  the  other  element? 

63.  The  molecular  weight  of  potassium  chloride  is 
74.2.     The  per  cent  of  potassium  in  the  compound  is 
52.56.     The  specific  heat  of  potassium  is  0.166.     What 
is  the  atomic  weight  of  the  element  ? 

64.  The   molecular  weight   of   lead  oxide.   PbO,  is 
221.3.     The  per  cent  of  lead  =  92.81.     Specific  heat  of 
lead  =  0.031.     What  is  its  atomic  weight  ? 

65.  A    compound   of   hydrogen   and   sulphur   has  a 
molecular  weight   of   34.     The    per   cent    of    sulphur 
in    the  compound  is  94.11.     Specific  heat   of   sulphur 
=  0.163.     What  is  its  atomic  weight  ? 

66.  A    compound  of   aluminum  and    chlorine  has  a 
molecular  weight  of  265.2.     Per  cent  of  aluminum  is 
20.36.     Specific  heat  of  aluminum  =  0.222.     What  is 
the  atomic  weight  of  aluminum  ? 


136     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

67.  Analysis  of   uranium  chloride    shows   the  com- 
position:  U,   62.7%;    Cl,  37.3%.     The   specific    heat 
of   metallic    uranium   is    0.027.     What  is  the    atomic 
weight  of  uranium  and  what  the  formula  of  the  chloride  ? 

68.  Find  the  atomic  weight  of  lead  from  the  follow- 
ing data :    the   molecular  weight  of   lead   sulphide    is 
249;    in  100  parts  of   lead   sulphide   there   are    83.13 
parts  of  lead ;  specific  heat  of  lead  is  0.031. 

69.  The  molecular  weight  of  arsenuretted  hydrogen 
is  78.     In  100  parts  there  are  96.15  parts  of  arsenic, 
and  the  specific  heat  of  arsenic  is  0.0814.     What  is  the 
atomic  weight  of  arsenic  ? 

70.  The   molecular  weight  of   carbon   disulphide  is 
76,  and  100  parts  yield  84.21    parts  of   sulphur;    the 
specific  heat  of  sulphur  is  0.163.     What  is  the  atomic 
weight  of   sulphur,  and  how  many  atoms  of   sulphur 
are  in  a  molecule  of  the  carbon  disulphide  ? 

71.  The  specific  heat  of  silver  is  0.056;    what  is  its 
atomic  weight  ? 

72.  If   35.5   g.  of   chlorine   unite   with   48.6  g.    of 
platinum  to  form  platinic  chloride  and  the  specific  heat 
of  platinum  is  0.0324,  what  is  (a)  the  atomic  weight  of 
platinum  and  (6)  the  formula  of  platinic  chloride  ? 

73.  A  compound   consists  of    P,  20.19;    O,    10.43; 
Cl,  69.38.     The  vapor  density  of  the  substance  in  the 
state  of  gas  is  77.95;  the  specific  heat  of  phosphorus 
is  0.1887.     Calculate  the  molecular  weight  of  the  com- 
pound and  the  atomic  weight  of  phosphorus. 

74.  Dumas   found,    on   heating    copper   oxide   in   a 
stream  of  dry  hydrogen,  that  a  certain  weight  of  this 


ATOMIC  AND  MOLECULAR  WEIGHTS          137 

substance  lost  59.789  g.  of  oxygen  and  yielded  67.282  g. 
of  water.  Calculate  from  these  numbers  the  atomic 
weight  of  hydrogen. 

75.  Marignac  obtained  314.894  g.  of  silver  nitrate 
from    200  g.  of   silver.     Further,  14.110  g.  of   silver 
nitrate  require  6.191  g.  of.  potassium  chloride  for  com- 
plete precipitation,  and  10.339  g.  of  silver  dissolved  in 
nitric  acid  require  5.120  g.  of  ammonium  chloride  for 
precipitation.     Calculate  the  atomic  weight  of  nitrogen 
from  these  data. 

76.  An  oxide  of  bismuth  contains  89.655%   of  bis- 
muth ;  calculate  the  equivalent  of  bismuth. 

77.  If  0.334  g.  of  metallic  silver,  dissolved  in  nitric 
acid,  yield  a  precipitate  of  silver  chloride  with  hydro- 
chloric  acid   which   weighed   0.4436   g.,    what   is   the 
equivalent  of  silver  ? 

78.  If  3.2  g.  of  silver  chloride,  heated  in  a  current 
of  hydrogen,  yield  2.4081  g.  of  metallic  silver,  what  is 
the  equivalent  of  silver  ? 

79.  If  5  g.  of  copper  oxide,  heated  in  a  current  of 
hydrogen,  yield  3.9915  g.  of  metallic  copper,  what  is 
the  equivalent  of  copper  ? 

80.  If  1.665  g.  of  lead  chloride  were  dissolved  in 
water,  and  silver  nitrate  was  added  to  the  solution,  and 
the  precipitated  silver  chloride  weighed  1.72  g.,  what  is 
the  equivalent  of  lead  ? 

81.  Mallet  found  that  8.2144  g.  of  ammonium  alum, 
dried  by  exposure  to  air  at  +  21°  C.  to  +  25°  C.,  yielded 
0.9258    g.    of   A12O3.     Taking    the    following    atomic 
weights:     O,  15.961;    S,    31.966;    N,  14.010,  find  the 
atomic  weight  of  aluminum. 


138     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

82.  Mallet  found  that  6.9617  g.  of  AlBr3  required 
8.4429  g.  of  Ag  for  precipitation  of  the  bromine.     If 
Ag=  107.649   and   Br  =  79.754,    what    is    the    atomic 
weight  of  Al  as  deduced  from  this  result  ? 

83.  Find  the  equivalent  of  aluminum  from  the  fol- 
lowing data:   (a)  5.2632  g.   of  the  metal  heated  with 
potash  gave   hydrogen  which,   when    burned,  yielded 
5. 2562  g.  of  water;     (6)  8.6492  g.  of  aluminum  bro- 
mide required  10.4897  g.  of  silver  for  complete  precipi- 
tation. 

84.  One  1.  of  mercury  vapor  at  the  standard  tempera- 
ture and  pressure  weighs  8.923  g.    On  heating  118.3938 
g.  of  mercuric  oxide,  Erdmann  and  Marchand  obtained 
109.6308  g.  of  mercury.     On  the  assumption  that  mer- 
curic oxide  is  formed  by  the  union  of  1  atom  of  mercury 
with  1  atom  of  oxygen,  what  light  do  these  facts  throw 
on  the  atomic  and  molecular  weights  of  mercury  ? 

85.  By  dissolving  0.4442  g.  of  metallic  cobalt  in  an 
acid,  177.4  cc.  of  hydrogen  at  +  10°  C.  and  750  mm. 
pressure  are  obtained.     The  specific  heat  of  the  metal 
is  0.107.     Calculate  the  atomic  weight  of  cobalt. 

86.  If  4.353  g.  of  potassium  bromide  required,  for 
complete  precipitation,  3.946  g.  of  silver  dissolved  in 
nitric  acid,  what  is  the  equivalent  of  bromine  ? 

87.  A  compound  has  the  following  percentage  com- 
position:  oxygen,  76.09%;   hydrogen,  1.59%;   nitro- 
gen, 22.32%.      One  1.  of   its   vapor   weighs  2.817  g. 
What  is  its  molecular  weight  and  formula? 

88.  A    hydrocarbon    consists    of    carbon,    93.75%; 
hydrogen,  6.25%.     The  density  (air)  of  its  vapor  is 
4.456.     What  is  its  formula  ? 


ATOMIC  AND  MOLECULAR  WEIGHTS  139 

89.  A  gas  has  the  following  composition :  nitrogen, 
30.56%  ;    oxygen,  69.44%.     One  1.  of  the  gas  weighs 
2.058  g.     What  is  its  molecular  weight  and  formula  ? 

90.  A  compound  has  the  following  percentage  com- 
position:    H,  1.19%;   O,  56.86%;   01,41.95%.     One 
1.  of  its  vapor  weighs  3.771  g.     What  is  its  molecular 
weight  and  formula? 

91.  If  4.5  g.  of  mercury  unite  with  oxygen  to  form 
4.86  of  mercuric  oxide,  and  the  specific  heat  of  mercury 
is  0.032,  what  is  its  atomic  weight? 

92.  If    25   g.    of  metallic   tin  were   converted   into 
stannic  oxide  by  heating  with  nitric  acid  and  then  ignit- 
ing, and  the  stannic  oxide  weighed  31.8  g.,  what  is  its 
atomic  weight  ?     The  specific  heat  of  tin  is  0.056. 

93.  Suppose  that  0.3697  g.  of  aluminum  liberated 
0.04106  g.  of  hydrogen  on  being  dissolved  in  a  strong 
solution  of  sodium  hydrate.     On  the  assumption  that 
alumina  is  a  sesquioxide,  A12O3,  find  from  these  data 
the  atomic  weight  of  aluminum. 


CHAPTER   XI 

Electro-chemical  Problems 

1.  A  current   deposits   16   g.  of  silver;  how   much 
copper  will  it  deposit  ? 

2.  What  current  strength  (in  amperes)  is  required 
to  deposit :  20  g.  of  silver  in  an  hour  ;  100  g.  of  iodine 
in  5  minutes ;  60  g.  of  antimony  in  3  hours  ? 

3.  A  current  deposits  1  g.  of  sodium ;    find  weight 
of  Ni  deposited. 

4.  If  a  current  deposits  32  g.  of  Cu,  how  many  g. 
of  Al,  Na,  Mg,  Pb,  will  it  deposit  ? 

5.  Two  electrolytic  cells,  one  containing  acidulated 
water  and  the  other  lead  nitrate  solution,  are   joined 
in  series,  and  the  same  current  is  passed  through  them 
until  25  cc.  of  hydrogen  are  liberated  in  the  first  cell. 
What  weight  of  lead  nitrate  will  be  decomposed  in  the 
other  cell  ? 

6.  How  many  g.  of  silver  will  be  deposited  from  a 
solution  of  silver  nitrate  by  a  current  of  2  amperes  in 
50  sec.  ? 

7.  How  many  g.  of  copper  will  be  deposited  from 
a  bath  of  copper  sulphate  by  a  current  of  5  amperes  in 
30  min.  ? 

8.  How  much   would   a   metal   platter   increase    in 
weight  if   it  were   nickel-plated  by  a  current   of   0.5 
ampere  running  5  hr.  ? 

140 


ELECTRO-CHEMICAL   PROBLEMS  141 

9.    What  is  the  current  strength  of  a  Daniell  cell 
if  its  copper  plate  gains  0.7  g.  in  40  min.  ? 

10.  How  much  current  would  be  needed  to  make  in 
3  hr.  a  copper  electrotype  shell  weighing  40  g.  ? 

11.  How  long  would  it  take  a  current  of  5  amperes 
to   produce    0.6    g.   of   hydrogen  by  decomposition  of 
water? 

12.  Find   the    electro-chemical    equivalent   for   zinc 
from  the  fact  that  one  of  the  zinc  plates  in  an  Edison 
chemical  meter   gains   726  g.  when   20  amperes   pass 
through  it  for  30  hr. 

13.  If  a  current  of  2  amperes  is  used  to  decompose 
water  and  produces  2.981  g.  of  oxygen  in  5  hr.,  what 
is  the  electro-chemical  equivalent  for  oxygen  ? 

14.  The  current  from  a  battery  liberates  in  a  given 
time  150  cc.  (measured  at  0°C.  and  760  mm.)  of  the 
mixed  gases  from  acidified  wtfter ;  if  this  same  current 
were   passed   through  a  solution   of   copper   sulphate, 
what  weight  of  copper  would  be  deposited  ? 

15.  How  many  coulombs  are    carried   by    and  will 
deposit :  20  g.  of  silver ;   15  g.  of  antimony ;   30  g.  of 
chlorine  ;  60  g.  of  phosphanion  (PO4)  ? 

16.  If   a   current    of   15  amperes   flows  for  1  hour 
and  20  minutes,  how  many  coulombs  will  pass  ?     How 
many  ampere-hours  will  that  give  ? 

17.  If  the  specific  resistance  of  copper  is  0.000001629, 
what  is  the  resistance  of  a  wire  200  m.  long  having  a 
cross  section  of  2  mm.2? 

18.  If   the   specific   resistance  of   German    silver  is 
0.0000209,  what  is    the  resistance  of   150  m.   of   wire 
having  a  cross  section  of  25  mm.2? 


142     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

19.  What  is  the  resistance  of  an  electric  light  carbon 
12  inches  long  by  |  inch  in  diameter,  when  its  specific 
resistance  is  0.07  ? 

20.  How  much  zinc  will  be  deposited  from  zinc  sul- 
phate by  3  amperes  in  10  minutes? 

21.  How  much  lead  will  be  deposited  by  a  current 
of  J  an  ampere  passing    for  90  minutes  through  lead 
chloride  ? 

22.  How  much  chlorine  would  be  liberated  by  J  an 
ampere  passing  through  dilute  hydrochloric  acid  for  13 
hours  ? 

23.  How  much  tin  will  be  deposited  by  5  amperes 
flowing  6  hours  through  a  solution  of  SnCl2  ? 

24.  How  many  amperes  will   it  take  to  deposit  2^ 
Ib.  of  copper  from  copper  sulphate  in  10  hours  ? 

25.  What  is  the  minimum  voltage  necessary  to  de- 
compose water  if  the  heat  of  combination  of  1  g.  of 
hydrogen  with  oxygen  is  34,180  calories  ? 

26.  If  zinc  bromide  requires  1.65  volts  to  decompose 
it,  what  is  the  heat  involved  by  the  equivalent  weight 
of  zinc  in  g.  combining  with  bromine  ? 

27.  If  1  g.    of   hydrogen,   combining  with  chlorine 
in  the  presence  of  water,  evolves  39,315  calories,  -what  is 
the  voltage  required  for  the  decomposition  of  hydro- 
chloric acid  ? 


CHAPTER   XII 

Analytical  Calculations  —  Strength  of  Solutions 

1.  If  a  solution  of  hydrochloric  acid  contained  44 
g.  of  that  substance  to  the  L,  how  many  cc.  of  the  solu- 
tion would  be  needed  to  neutralize  20  cc.  of  the  solution 
of  sodium  hydroxide  containing  60  g.  to  the  1.? 

2.  What  weight  of  sodium  hydroxide  will  neutral- 
ize 100  g.  of  sulphuric  acid  ?     What  weight  of  potas- 
sium hydroxide  will  neutralize  the  same  ? 

3.  If  in  neutralizing  a  certain  amount  of  nitric  acid 
with  sodium  hydroxide,  7.85  cc.  of  water  are  formed, 
how  much  nitric  acid  and  how  much  sodium  hydroxide 
have  been  employed  ? 

4.  llow  many  g.  of  a  5  %  solution  of  KOH  will  be 
required  to  neutralize    10  g.    of   a    10  %    solution   of 
H2S04? 

5.  If  10  g.  of  commercial  caustic  soda,  dissolved  in 
water,  required  116.3  g.  of  a  10  %  sulphuric  acid  to 
neutralize  the  solution,  what  percentage  of  pure  NaOH 
did  the  substance  contain  ? 

6.  If  10  g.  of  commercial  nitric  acid  were  exactly 
neutralized  by  the  addition  of  58.6  g.  of  a  10  %   solu- 
tion of  potassium  hydroxide,  what  was  the  strength  of 
the  acid  in  pure  HNO3  ? 

143 


144     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

7.  If   a   solution    contained    50   g.    of    ammonium 
hydroxide  to  the  1.,  how  many  cc.  of  a  10  %  solution  of 
hydrochloric  acid  will  be  needed  to  neutralize  60  cc.  of 
the  ammonium  hydroxide  solution  ? 

8.  What  weight  of  potassium  hydroxide  will  neu- 
tralize 36.2  g.  of  hydrochloric  acid? 

9.  What  weight  of  sodium  hydroxide  will  neutral- 
ize 36.2  g.  of  hydrochloric  acid  ? 

10.  What  weight  of  potassium  hydroxide  will  neu- 
tralize 62.7  g.  of  nitric  acid  ? 

11.  What  weight  of  sodium  hydroxide  will  neutral- 
ize 62.7  g.  of  nitric  acid  ? 

12.  What  weight  of  potassium  hydroxide  will  neu- 
tralize 97.6  g.  of  sulphuric  acid? 

13.  What  weight  of  sodium  hydroxide  will  neutral- 
ize 97.6  g.  of  sulphuric  acid? 

14.  Suppose   we   have  a   molar  solution  of   sodium 
hydroxide  and  a  hydrogen  chloride  solution  of  unknown 
strength.     If  50  cc.  of  the  former  require  62  cc.  of  the 
latter  for  neutralization,  what  is   the  strength  of  the 
hydrochloric  acid  solution  ? 

15.  Calculate  the  weight  of  sodium  hydroxide  that 
would    be  neutralized   by  50  cc.  of  a  solution  of  sul- 
phuric acid  of  density  1.23  and   containing  31%    by 
weight  of  pure  acid. 

16.  What  volume  of  centinormal  sulphuric  acid  solu- 
tion would  be  required  to  neutralize  0.008  g.  of  K2CO3  ? 

17.  HBr  solution  having  a  density  of  1.515  contains 
49.8  %  of  the  gas.     How  many  g.  AgNO3  are  needed 
to  precipitate  250  cc.  of  the  solution? 


ANALYTICAL  CALCULATIONS  145 

18.  If  75  cc.  of    HC1  solution  neutralize  60  cc.  of 
NaOH  containing  0.003  g.  of  the  alkali  per  cc.,  what 
was  the  weight  of  the  acid  in  1  cc.  of  its  solution  ? 

19.  A  solution  of  KOH  contains  0.02  g.  per  cc.  and  15 
cc.  of  it  neutralize  40  cc.  of  an  HC1  solution.     Find  the 
number  of  g.  of  HC1  contained  in  30  cc.  of  the  solution. 

20.  How   much  ammonium  hydroxide,  sp.  gr.  0.88, 
and  water  will   have  to   be  mixed  to  give  200  cc.  of 
ammonium  hydroxide,  sp.  gr.  0.96? 

21.  How  much  nitric  acid,  sp.  gr.  1.42,  and  water 
are  needed  to  make  6  1.  of  nitric  acid,  sp.  gr.  1.26  ? 

22.  How  much  sulphuric  acid,  sp.  gr.  1.7,  and  how 
much  water  are  required  to  make  400  cc.  of  sp.  gr. 
1.18? 

23.  How  much   ammonium  hydroxide,    sp.  gr.   0.9, 
and  water  must  be  mixed  to  give  4  1.  of  sp.  gr.  0.96  ? 

24.  Given  2  1.  of  dilute  sulphuric  acid,  sp.  gr.  1.2, 
which  is  to  be  used  up  in  diluting   concentrated   sul- 
phuric acid,  sp.  gr.  1.82,  to  an  acid  of  sp.  gr.  1.3,  how 
much  concentrated  acid  must  be  added  ? 

25.  A  solution  of  lime  water  contains  5  g.  of  lime  to 
the  1.;  how  many  cc.   of  N/10  H2SO4  are  needed  to 
precipitate  all  of  the  lime  from  10  1.  of  the  lime  water 
solution  ? 

\  26.  If  300  cc.  of  a  solution  of  caustic  potash  contain- 
ing 40  g.  KOH  per  1.  are  required  to  neutralize  100  cc. 
of  sulphuric  acid  and  the  same  volume  of  nitric  acid, 
what  is  the  amount  of  acid  in  each  solution  ? 

27.  What  volume  of  aqueous  hydrochloric  acid,  con- 
taining 36.5  g.  HC1  per  1.,  will  be  required  to  neutral- 
ize 224.5  g.  of  Na2CO3, 10  H2O  ? 


146     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

28.    How  many  Ib.  of  15  %  HC1  are  needed  to  neu- 
tralize 2000  Ib.  of 


^  29.  Calculate  the  weight  of  crystallized  oxalic  acid 
(C2H2O4,  2  H2O)  required  for  a  solution  which  is  to  be 
made  up  to  500  cc.  in  volume  at  N/2  strength. 

30.  If  1  1.  of  a  solution  of  sodium  hydroxide  contains 
35  g.  of  NaOH,  how  many  g.  of  nitric  acid  would  be 
needed  to  neutralize  exactly  60  cc.  of  the  solution  ? 

31.  How  much  of   the   following  substances  are  in 
their  molar  solutions  :  hydrogen  bromide  ;    potassium 
hydroxide  ;  and  potassium  iodide  ? 

32.  How  much  of  a  tenth-normal  hydrochloric  acid 
solution  is  necessary  to  neutralize    3  g.   of  strontium 
hydroxide  ? 

33.  Determine  the  normality  of  a  sodium  dichromate 
solution,  50  cc.   of  which  oxidized  3.85  g.   of  ferrous 
ammonium  sulphate  [FeSO4,  (NH4)2SO4,6  H2O]  to  the 
ferric  salt. 

34.  How  many  g.  of  10  %  (by  weight)  solution  of 
barium  chloride  are  needed  to  precipitate  as  barium 
sulphate  the  SO4  in  2  g.  of  pure  magnesium  sulphate? 

35.  How  many  g.  of  a  5  %  solution  of  ammonium 
oxalate  are  needed  to  precipitate  completely  as  calcium 
oxalate  the  lime  in  1  g.  of  calcium  carbonate  ? 

36.  How  many  g.  of  15  %  solution  of  NaNH4HPO4 
are  necessary  to  precipitate  completely  the  zinc  in  a 
solution  containing  0.50  g.  of  zinc? 

37.  How   many   Ib.   of  25%  sulphuric  acid  will   be 
required    to    neutralize    2000    Ib.     of    NaHCO3  ;     of 
CaCO3? 


ANALYTICAL   CALCULATIONS  147 

38.  How  much  iron  is  present  in  10  cc.  of  ferrous  sul- 
phate solution,  15  cc.  of  which  required  60  cc.  of  a  solu- 
tion of  K2O2O7  containing  4.902  g.  of  the  dry  salt  per  1.? 

39.  A  solution,  A,  contains  100  g.  of  KOH  to  the  1. 
A  solution,  B,  contains  100  g.  of  H2SO4  to  the  1.     What 
volume  of  solution  A  is  needed  to  neutralize  exactly 
25  cc.  of  S? 

40.  Calculate  the  number  of  g.  per  1.  to  give  normal 
solutions  of  NaCl ;  ofBad2;  of  Na3PO4 ;  of  KOH. 

41.  Calculate  the  amounts  needed  to  make  5  1.  of  N/10 
silver  nitrate ;   2  1.  of  N/10  sodium  bromide ;   1  1.   of 
N/20  K2CO3. 

42.  What  weight  of  iron  in  the  ferrous  condition  will 
100  cc.  of  N/10  KMnO4  oxidize? 

43.  4  g.  of  pure  KMnO4  are  dissolved  and  diluted 
to  1  1.  ;  how  many  mg.  of  active  oxygen  are  contained 
in  each  cc.  ?     What  will  be  its  strength  in  terms  of  iron  ; 
of  oxalic  acid? 

44.  If  35  g.  of  FeSO4,7H2O  are  dissolved  and  di- 
luted to  1  1.,  how  many  ing.  of  active  oxygen  will  each 
cc.  absorb? 

45.  How  many  g.  of  NaOH  must  be  added  to  2  1.  of 
NaOH  solution,  the  strength  of  which  is  1  cc.  =  0.045  g. 
H2SO4,    to   make    it  a   normal  solution?     How  much 
water  to  make  it  N/2  solution  ? 

46.  How  many  g.  per  1.  of  KMnO4  will  give  a  so- 
lution of  such  strength  that  1  cc.  =  1  %  of  iron  when 
0.5  g.  is  taken  for  analysis? 

47.  Given  a  solution   of    K2Cr2O7,  1  cc.  =  0.005  g. 
iron,  how  many  g.  of  KMnO4  per  1.  will  give  a  solution 
of  equal  oxidizing  strength? 


148     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

48.  What  volumes  of  N/2  and  of  N/10  H2SO4  must 
be  mixed  to  give  2  1.  of  N/5  H2SO4? 

49.  A  solution  of  hydrochloric  acid  is  desired  to  be 
made  exactly  normal.     If  40  cc.  of  the  solution  neu- 
tralized 50  cc.  of  0.84  N  sodium  hydroxide  solution, 
what  volume  of  water  must  be  added  per  100  cc.  of  the 
acid  solution  ? 

50.  A  solution  of  sodium  hydroxide  is  desired  to  be 
made  exactly  0.5  N.     If  32  cc.  of  the  solution  at  hand 
were  required  for  the  titration  of  28  cc.  of  0.8  N  hy- 
drochloric acid,  what  volume  of  water  must  be  added  per 
100  cc.  of  the  alkaline  solution  ? 

51.  A  solution  of  sodium  carbonate  is  desired  to  be 
made  exactly  0.05  N.     If  24  cc.  of  the  solution  at  hand 
neutralized  9.6  cc.  of  0.12  N  hydrochloric   acid   solu- 
tion, what  weight  of  anhydrous  salt,  Na2CO3,  must  be 
added  per  100  cc.  of  solution? 

52.  Calculate  the  volume  of  nitric  oxide  that  could 
be  evolved  by  the  action  of  copper  upon  1000  cc.  of  a 
N/7  nitric  acid  solution. 

53.  An  excess  of  iron  sulphide  was  added  to  500  cc. 
of  a  solution  of  sulphuric  acid.     The  volume  of  hydro- 
gen sulphide  set  free  measured  4640  cc.     Calculate  the 
normality  of  the  acid. 

54.  An  excess  of  sodium  sulphite  was  added  to  400 
cc.  of  a  solution  of  hydrochloric  acid.     The  volume  of 
sulphur  dioxide  set  free  measured  5600  cc.     Calculate 
the  normality  of  the  acid. 

55.  Suppose  that  1400  cc.  of  ammonia  were  passed 
into  500  cc.  of  N/2  hydrochloric  acid  solution.     Calcu- 
late the  normality  of  the  hydrochloric  acid  still  present. 


ANALYTICAL   CALCULATIONS  149 

56.  If  50  cc.  of  N/5  hydrochloric  acid  solution  neu- 
tralized 40  cc.  of  an  unknown  alkaline  solution,  and  300 
cc.  of  a  sulphuric  acid  solution  neutralized  60  cc.  of  this 
same  alkaline  solution,  what  is  the  normality  of  the  sul- 
phuric acid? 

57.  If  200  cc.  of  a  barium  hydroxide  solution  were 
required  in  the  titration  of  40  cc.  of  an  acid  solution, 
and  100  cc.  of  this  acid  solution  exactly  neutralized  80 
cc.  of  N/2  alkaline  solution,  what  is  the  normality  of 
the  barium  hydroxide  solution  ? 

58.  If  600  cc.  of  a  sulphuric  acid  solution,  when  acted 
upon  by  an  excess  of  zinc,  evolved  1242  cc.  of  hydrogen, 
what  is  the  normality  of  the  acid  ? 

59.  If  400  cc.  of  an  acid  solution,  when  acted  upon 
by  an  excess  of  zinc,  evolved  2430  cc.  of  hydrogen, 
measured  over  water  at  +21°  C.  and  747.5  mm.,  what 
is  the  normality  of  the  acid? 

60.  Calculate  the  normality  of  a  solution  of  potassium 
carbonate,  200  cc.  of  which,  when  treated  with  an  excess 
of  acid,  evolved  4502  cc.  of  carbon  dioxide. 

61.  A  slight  excess  of  barium  chloride  solution  was 
added  to  400  cc.  of  a  solution  of  sulphuric  acid.     From 
the  weight  of  barium  sulphate  precipitated,  4.12  g., 
calculate  the  normality  of  the  acid. 

62.  If  50  cc.  of  a  solution  of  hydrogen  peroxide  were 
required  to  decolorize  400  cc.  of  N/5  potassium  perman- 
ganate solution  (acidulated),  what  is  the  percentage 
concentration  of  the  hydrogen  peroxide  solution? 

63.  Calculate  the  weight  of  a  crystallized  oxalic  acid 
required  for  the  reduction  of  100  g.  of  potassium  per- 
manganate in  acid  solution.     What  volume  of  carbon 
dioxide,  at  standard  conditions,  would  be  liberated  ? 


150     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

64.  If  400  cc.  of  N/4  potassium  hydroxide  solution 
were  required  for  the  neutralization  of  600  cc.  of  an 
unknown  acid  solution,  what  is  the  normality  of  this 
acid  solution? 

65.  If  500  cc.  of  N/10  acid  solution  were  required 
for  the  neutralization  of  25  cc.  of  a  solution  of  sodium 
hydroxide,  what  is  the  normality  of  this  latter  solution? 

66.  What   volume    of    N/10    acid    solution    will   be 
required  in   the  ttitration  of   440   cc.    of   N/4  sodium 
hydroxide  solution? 

67.  What  volume  of  N/6  alkaline  solution  will  be  re- 
quired in  the  titration  of  254  cc.  of  N/10  acid  solution? 

68.  Calculate  the  weight  of  hydrogen  chloride  pres- 
ent in  400  cc.  of  a  hydrochloric  acid  solution  which  re- 
quired 320  cc.  of  N/4  alkaline  solution  for  titration. 

69.  Calculate  the  weight  of  sulphuric  acid  present  in 
150  cc.  of  a  solution  which  required  48.1  cc.  of  0.78  N 
alkali  for  titration. 

70.  An  excess  of  silver  nitrate  solution  was  added  to 
350  cc.   of  a  solution  of  hydrochloric  acid.     The  pre- 
cipitate of  silver  chloride  weighed  7.54  g.     Calculate 
the  normality  of  the  acid. 

71.  The  bromine  set  free  by  the  action  of  manganese 
dioxide  upon  a  hydrobromic  acid  solution  was  passed 
into  a  solution  of  potassium  iodide.     If  200  cc.  of  N/10 
sodium  thiosulphate  solution  were  required  for  the  ti- 
tration of  the  free  iodine,  what  is  the  weight  of  the 
bromine  evolved? 

72.  Determine  the  purity  of  a  sample  of  manganese 
dioxide,  2.2  g.  of  which,  with  excess  of  hydrochloric 


ANALYTICAL   CALCULATIONS  151 

acid,  set  free  sufficient  chlorine  to  liberate  a  quantity  of 
iodine  that  required  250  cc.  of  N/5  sodium  thiosulphate 
solution  for  titration. 

73.  What  weight  of  iron  will  be  required  for  inter- 
action with  400  cc.  of  N/5  hydrochloric  acid? 

74.  What  weight  of  sodium  carbonate  will  be  required 
for  interaction  with  600  cc.   of  N/8  sulphuric  acid? 
What  volume  of  carbon  dioxide  (at  standard  conditions) 
will  be  evolved  ? 

75.  What   weight   of    sodium   hydrogen   carbonate, 
NaHCO3,  will  be  required  for  interaction  with  600  cc. 
of  N/8  sulphuric  acid?     What  volume  of  carbon  diox- 
ide will  be  evolved? 

76.  If  50  cc.  of  an  acidulated  potassium  permanga- 
nate solution  were  reduced   by  2.4  g.    of   anhydrous 
oxalic  acid,  what  is  the  normality  of  the  permanganate 
solution? 

77.  WThat  weight  of  sulphur  dioxide  will  be  oxidized 
by  50  g.  of  potassium  permanganate  in  alkaline  solution  ? 

78.  What  weight  of  sodium  dichromate  must  enter 
into  reaction  with  a  hydrochloric  acid  solution  in  order 
to  liberate  100  g.  of  chlorine  at  standard  conditions? 

79.  Determine  the  normality  of  a  potassium  dichro- 
mate solution,  25  cc.  of  which  oxidized  1.24  g.  of  ferrous 
sulphate  to  the  ferric  salt. 

80.  What  volume  of  hydrogen  sulphide,  at  4-  24°  C. 
and   750  mm.    pressure,   can   be   oxidized  by  10  g.   of 
potassium  dichromate  in  acid  solution? 

81.  What  weight  of   potassium  dichromate,  in  acid 
solution,  will  be  reduced  by  1653.5  cc.  of  sulphur  diox- 
ide at  +  22°  C.  and  745  mm.  pressure? 


152     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

82.  What  volume  of  hydrogen  sulphide  will  be  re- 
quired for  the  reduction  of  100  g.  of  ferric  chloride, 
FeCl3,  to  the  ferrous  salt  ? 

83.  What  volume  of  gaseous  product  may  be  obtained 
in  the  decomposition  of  100  cc.  of  ammonia  by  heated 
cupric  oxide  ? 

84.  What  volume  of  hydrogen  sulphide  will  be  re- 
quired to  reduce  200  cc.  of  N/10  potassium  dichromate 
solution  (acidulated)  ? 

85.  Calculate  the  volume  of  hydrogen  sulphide,  at 
standard  conditions,  that  can  be  oxidized  by  4  g.  of 
potassium  permanganate  in  acid  solution. 

86.  What  weight  of  sulphur  dioxide  can  be  oxidized 
by    200  g.  of   potassium    permanganate  in  acid   solu- 
tion ? 

87.  A  sample  of  sodium  chromate,  weighing  1.6780 
g.,  gave  upon  analysis  1.4620  g.   of  sodium  sulphate. 
What   was   the    percentage    of    sodium    oxide   in   the 
sample  ? 

88.  Calculate  the  weight  of  sulphur  precipitated  in 
the  reduction  of  100  g.  of  ferric  chloride  to  the  ferrous 
salt  by  the  action  of  hydrogen  sulphide. 

89.  What  weight  of  potassium  dichromate  will  1000 
cc.  of  hydrogen  sulphide  reduce  in  acid  solution  ? 

90.  Calculate  the  percentage  purity  of  a  quantity  of 
potassium  ferrocyanide,  0.5793  g.  of  which  gave  upon 
analysis  0.4650  g.  of  potassium  sulphate. 

91.  What  is  the  percentage  of  potassium  sulphate  in 
a  sample  of  common  alum  which  analyzed  -33.51  %  sul- 
phur trioxide? 


ANALYTICAL   CALCULATIONS  153 

92.  What  is  the  percentage  of  copper  carbonate  in  a 
sample  of  malachite  which  on  analysis  gave  57.1  %  copper  ? 

93.  A  sample  of  carnallite  (KC1,  MgCl2,  6  H2O)  on 
analysis  gave  35.34%  chlorine;  what  is  the  percentage 
of  magnesium  chloride  present? 

94.  Calculate  the  percentage  purity  of  a  sample  of 
marble  which  on  analysis  gave  39.6%  calcium. 

95.  Calculate  the  percentage  of  potassium  chloride 
in  a  sample  of  carnallite  (KC1,  MgCl2,  6  H2O)  which  on 
being  analyzed  gave  37.72%  chlorine. 

96.  Calculate  the  percentage  of  calcium  oxide,  CaO, 
present  in  a  sample  of  marble,  CaCO3,  which  on  being 
analyzed  gave  43.8%  carbon  dioxide. 

97.  Two  g.  of  impure  potassium  dicarbonate  required, 
when  titrated  cold,  in  a  dilute  solution,  6  cc.  of  N/10 
H2SO4;    2  g.,  when  titrated  boiling  hot,  required  18 
cc.   of  normal  H2SO4.     What  are  the  percentages  of 
K2CO3andof  KHCOo? 

A  O  O 

98.  What  volumes  of  N/2  and  of  N/10  H2SO4  must 
be  mixed  to  give  2  1.  of  N/5  H2SO4? 

99.  A  N/10  iodine  solution  is  2  %  too  strong.     How 
many  cc.  of  a  N/100  iodine  solution  must  be  added  to 
1  1.  to  make  it  right? 

100.  How  much  more  normal  NaOH  will  it  take  to 
neutralize  1  g.  of  NaHSO4  than  normal  KOH  to  neu- 
tralize 1  g.  KHSO4? 

101.  Suppose  that  0.2  g.   of  a  nitrogenous  organic 
compound  were  heated  writh  soda  lime  and  the  NH3 
evolved  was  caught  in  50  cc.  N/10  HC1,  and  that  the 
excess  of  HC1  was  neutralized  by  14  cc.  of  N/5  NaOH  ; 
what  was  the  percentage  of  nitrogen  ? 


154     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

102.  Iii  1   g.   of   an   antimony  alloy    the    antimony 
was  determined  by  N/10  Na2S2O3  and  24.2  cc.   were 
required  ;   what  is  the  percentage  of  antimony  ? 

103.  What  amount  of  type  metal  must  be  taken  for 
analysis  so  that  the  burette  shall  read  percentage  of 
antimony  when  N/10  Na2S2O3  is  used? 

104.  Five  g.  of  bleaching  powder  were  mixed  in  a 
mortar  with  water  and  diluted  to  1  1. ;    50  cc.  of  this 
required  30  cc.  of  N/10  Na3AsO3  solution.     What  is 
the  percentage  of  available  chlorine  ?    Under  these  con- 
ditions, what  fraction  of  normal  will  read  percentage 
direct? 

105.  To  50  cc.  of  a  solution  of  chlorine  an  excess  of 
potassium  iodide  was  added ;  the  liberated  iodine  was 
then  estimated  by  a  N/10  solution  of  Na2S2O3,  starch 
being  used  as  an  indicator;    and  22.5  cc.  of  Na2S2O3 
solution  were  needed.     What  is  the  strength  of  the 
chlorine  solution? 

106.  How  much  more  normal  NaOH  will  it  take  to 
neutralize  1  g.  of  HC1  than  1  g.  of  HBr? 

107.  How  many  g.  per  1.  of  K2Cr2O7  will  give  a  solu- 
tion of  such  strength  that  1  cc.  =  1  %  of  iron  when  0.60 
g.  is  taken  for  analysis  ? 

108.  How  many  g.  of  Na2S2O3,  5  H2O  per  1.  will  give 
a  solution  such  that  1  cc.  =0.5%    Cu  when  1  g.  is 
taken  for  analysis? 

109.  How    much   water   must  be  added  to   2  1.   of 
KMnO4,  1  cc.  =  0.0065  g.  iron,  to  make  it  N/10? 

110.  How  much  water   must  be  added   to    3  1.   of 
K4Fe(CN)6,   1   cc.  =  0.0115  g.   zinc,  to  make  it  read 
percentage  directly  when  1  g.   is  taken  for  analysis? 


ANALYTICAL  CALCULATIONS  155 

111.  Given  a  solution  of  K2Cr2O7,  1  cc.  =  0.0042  g. 
Fe,  how  many  g.  per  1.  of  KMnO4  will  give  a  solution 
of  equal  strength? 

112.  Given  a  solution  of  KMnO4,  1  cc.  =  0.0056  g. 
of  iron,  what  is  its   strength  in  terms  of  manganese 
by    the  Volhard   method   and   by   the  Ford- Williams 
method? 

113.  What  is  the  strength  of  N/10  KMnO4  in  terms 
of  H2C2O4;   of  CaO  ;   of  CaCO8;   of  CaSO4? 

114.  What  is  the  strength  of  N/10  KMnO4  in  terms 
of  P  and  of  MoO3  according  to  Noyes'  method? 

115.  What  is  the  strength  of  a  N/10  sodium  thio- 
sulphate  solution  in  terms  of  iodine ;  of  copper  ? 

116.  What  is  the  strength  of  a  N/5  iodine  solution 
in  terms  of  SO2  ;   H2SO3;  Na2SO3? 

117.  How  many  cc.  of  N/5  Na2S2O3  solution  will  be 
required  to  react  with  the  iodine  liberated  by  20  cc.  of 
a  N/10  K2O2O7  solution? 

118.  How  many  g.   of  copper  will  give,  when  pre- 
cipitated by  potassium  iodide,  sufficient  iodine  to  re- 
quire 20  cc.  of  N/10   SO2  solution?     How  many  for 
10  cc.  of  N/10  Na2S2O3  solution? 

119.  Five  g.  of  pig  iron  took  12  cc.  of  N/100  iodine 
solution ;  what  is  the  percentage  of  sulphur  ? 

120.  If   1.5   g.    of   pig   iron   took    78  cc.    of   N/10 
KMnO4,  what  is  the  percentage  of  phosphorus? 

121.  How  much  NaOH  must  be  added  to  1.890  1.  of 
NaOH  solution,  the  strength  of  which  is  1  cc.  =  0.045  g. 
H2SO4,  to  make  it  normal?     How  much  water  to  make 

it  N/2? 


156     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

122.  One  g.  of  a  rock  gave,  on  analysis :     combined 
sodium  and  potassium  sulphates,  0.150  g.  ;    and  plati- 
num from  K2PtCl6,  0.1127  g.     What  are  the  percentages 
of  K2O  andNa2O? 

123.  Which  is  more  economical  for  neutralizing  an 
alkali,  60  %  HNO3  at  6  cts.  per  Ib.  or  20  %  HC1  at  3 
cts.  per  Ib.  ? 

124.  Which  is  the  more  economical  oxidizing  agent, 
KNO3  at  5  cts.  a  Ib.  or  NaNO3  at  51  cts.  a  Ib.  ? 

125.  Calculate  the  number  of  g.  per  1.  to  give  normal 
solutions  of  oxalic  acid;    of  tartaric  acid;    of   acetic 
acid ;  of  citric  acid. 

126.  Calculate  the  number  of  g.  per  1.  to  give  half 
normal  solutions  of  I ;  of  Na2S2O3,  5  H2O  ;  of  SO2. 

127.  Calculate  the  amounts  necessary  to  make  2  1. 
of  N/10  NaCl  and  NaBr. 

128.  Calculate  the  strength  of  N/20  KMnO4  to  be 
used  in  titrating  K4Fe(CN)6. 

129.  What  is  the  strength  of  N/10  KMnO4  in  terms 
of  Fe;  Fe2O8;   Fe3O4;  FeSO4,  7H2O? 

130.  How  many  g.  of  oxalic  acid  in  a  molar  and  in 
a  normal  solution? 

131.  How  many  cc.  of  a  N/3  solution  of  AgNO3  will 
precipitate  20  cc.  of  a  10%  sodium  chloride  solution? 

132.  What  weight  of  As2O3  will  be  necessary  to  make 
a  twice  molar  and  a  N/2  solution  ? 

133.  One  g.  of  coal   gave   0.2634  g.  of   BaSO4   by 
Eschka's  Method;    1  g.  of  MgO  and  0.5  g.  of  Na2CO3 
were  used.     It  was  found  that  both  contained  sulphur ; 


ANALYTICAL  CALCULATIONS  157 

10  g.  of  MgO  and  5  g.  of  Na2CO3  (together)  gave 
0.1654  g.  of  BaSO4.  What  is  the  percentage  of  sul- 
phur in  the  coal? 

134.  Suppose  that  1  g.  of  silver  is  dissolved  in  nitric 
acid  and  to  it  is  added  0.25  g.  of  pure  dry  sodium  chlo- 
ride.   What  percentage  of  the  silver  remains  in  solution  ? 

135.  Suppose   that   0.25   g.    of   sodium   bromide   is 
added  to  a  solution  of  1  g.  of  silver;  what  percent- 
age of  silver  remains  in  solution? 

136.  A  dolomite  contains  98  %  of  calcium  and  mag- 
nesium  carbonates,  2  %  of   SiO2,  and  10  %   of  MgO ; 
what  is  the  percentage  of  CO2? 

137.  Calculate  the  chemical  factors  for  (a)   (NH4)2O 
from    2NH4C1,   PtCl4 ;     (5)  for  K  in    2  KC1,   PtCl4; 
(<?)  for  P  in  Mg2P2O7 ;   (cT)  for  Fe2O3  from  Fe3O4. 

138.  If  0.5  g.  of  platinum  remains  after  the  ignition 
of  the  precipitate  of  the  double  salt,  2  NH4C1,  PtCl4, 
derived  from  1  g.  of  an  ammonium  compound,  calculate 
the  percentage  of  NH3  in  the  latter.     2  NH4C1,  PtCl4  = 
2NH3+2HCl  +  2Cl2  +  Pt. 

139.  What  weight  of  Mn3O4  corresponds  to  1  g.  of 
Mn2P207? 

140.  How  many  cc.  of  aqueous  ammonia  (sp.  gr.  == 
0.96),  containing  9.90%  of  NH3  by  weight,  will  be  re- 
quired to  precipitate  the  iron  as  Fe(OH)3  from  1  g. 
of  (NH4)2SO4,  FeSO4,  6  H2O  ? 

141.  How  many  cc.  of  HNO3  (sp.  gr.  =  1.135),  con- 
taining 20  %  of  HNO3  by  weight,  are  required  to  oxi- 
dize the  iron  in  1  g.  of  FeSO4,  (NH4)2SO4,  6  H^O,  in 
the  presence  of  sulphuric  acid?     6  FeSO4  +  2  HNO3  + 
3  H2S04  =  3  Fe2(S04)3  +  2  NO  +  4  H2O.     . 


158     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

142.  The  ignited  precipitate  of  Fe2O3  -f-  A12O3  from 
1.5  g.  of  a  silicate  weighs  0.4069  g. ;  this  mixture  loses 
0.0200  g.  when  ignited  in  hydrogen.     What  is  the  per- 
centage of  Fe2O3  and  A12O3  in  the  sample?     Fe2O3 -f 
3  H2  =  2  Fe  +  3  H2O. 

143.  How  many  cc.  of  "  magnesia  mixture  "  (64  g. 
MgCl2  per  1.)  will  be  required  to  precipitate  the  arsenic 
from  0.2  g.  As2S3  after  oxidation  to  arsenic  acid? 

H3 As04  +  MgCl2  +  3  NH4OH  =  MgNH4  AsO4  + 
2  NH4C1  +  3  H20. 

144.  How  many  cc.  of  sulphuric  acid  (sp.  gr.  =  1.75), 
containing  81  %  H2SO4  by  weight,  are  necessary  to  re- 
place the  nitric  acid  in  the  nitrates  formed  from  5  g. 
of  a  brass  containing  65  %  Cu,  34.5  %  Zn,  and  0.5  %  Pb? 

145.  If  5.23  g.  of  brass  yield  0.0345  g.  of  PbSO4, 
and  subsequently  0.0031  g.  of  PbO2  on  electrolysis  of 
the  filtrate,  what  is  the  percentage  of  Pb  in  the  brass? 

146.  If  in  the  analysis  of  a  brass  containing  65% 
copper,  an  error  is  made  in  weighing  a  5  g.  portion,  by 
which  0.001  g.  too  much  is  weighed  out,  what  would 
be  the  percentage  of  copper  as  determined?     If  the 
same  error  is  made  in  weighing  0.2  g.  of  apatite  con- 
taining 40  %  P2^5'  wnat  will  be  the  apparent  percent- 
age?     What    will    be   the   percentage   error    in   each 
case? 

147.  If  the  dry  cupric  sulphide  from  0.82  g.  of  brass 
loses  0.1345  g.   on  ignition  in  hydrogen,  what  is  the 
percentage  of  copper  in  the  brass?     2  CuS  =  Cu2S  +  S. 

148.  If  1.5  g.  of  glass  yield  0.38  g.  KC1  +  NaCl, 
from  which  0.646  g.  2  KC1,  PtCl4  is  obtained,  what  is 
the  percentage  of  Na2O  in  the  glass? 


ANALYTICAL   CALCULATIONS  159 

149.  How  many  cc.  of  an  ammonium  oxalate  solu- 
tion [(NH4)2C2O4,  H2O]   (40  g.  per  1.)    are   required 
to  precipitate  the  calcium  as  oxalate  from  1  g.  of  apa- 
tite   [Ca3(PO4)2,  CaCl2]?     How  many  cc.    of    "mag- 
nesia mixture"  (containing  64  g.    MgCl2  per  1.)  are 
necessary  to  combine  with  the  phosphoric  acid  in  the 
same  weight  of  apatite  ? 

150.  If  a  calcium  oxalate  precipitate  (which  is  con- 
taminated by  silica)  from  0.83  g.  of  dolomite  is  ignited 
under  such  conditions  that  the  decomposition  products 
may  be   passed   through  Ba(OH)2  solution,  and   the 
resulting  precipitate  of  barium  carbonate  is  found,  on 
drying,  to  weigh  0.9500  g.,  what  is  the  percentage  of 
CaO  in  the  sample? 

151.  How  many  cc.  of  a  potassium  tetroxalate  solu- 
tion (KHC2O4,  C2H2O4,  2  H2O),  containing  50  g.  per 
1.,  would  be  required  to  precipitate  the  calcium  from 
1  g.  of  a  sample  of  dolomite  yielding  2%  Fe2O3,  10% 
MgO,  and  45%   CO2,  assuming  the  iron,  magnesium, 
and  calcium  to  be  present  wholly  as  carbonates,  the 
iron  as  ferrous  carbonate? 

152.  A  mixture  of  BaO  and  CaO  weighing  0.2438  g. 
yields   0.4876   g.    of   mixed   sulphates.     What  is   the 
weight  of  each  oxide  in  the  original  mixture? 

153.  Calculate  the  percentage  of  pure  Na2CO3  in  an 
impure  sample  from  the  following  data :    crucible  + 
SiO2  =  20.0697   g. ;      crucible  +  SiO2  +  Na2CO3    (im- 
pure) =  20.3264  g.  ;  crucible  +  SiO2  (excess)  +Na,2SiO3 
(after  fusion)  =  20.2239  g.     Assume  the  reaction  to  be 
Na2CO3  +  Si02  =  Na2Si03  +  CO2. 

154.  A  sample  of  pyrite  weighing  0.5  g.  yields  1.6  g. 
BaSO4.     Calculate  the  per  cent  of  FeS2  in  the  sample. 


160     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

155.  How   much  crude   cream   of  tartar  should   be 
taken  for  an  analysis  in  order  that  the  number  of  cc. 
of  N/2  NaOH  solution  required  to  react  with  it  shall 
represent  directly  the  percentage  of  KHC4H4O6  ?    How 
much  oxalic  acid  in  order  that  each  cc.  of  N/10  KMnO4 
may  represent  1  %  C2H2O4,  2  H2O? 

KHC4H4O6  +  NaOH  =  KNaC4H4O6  +  H2O. 

156.  What  weight  of  potassium  ferrocyanide  [K4Fe 
(CN)6,  3  H2O]   should  a  normal   solution   contain   for 
use  as  a  reducing  agent? 

10  K4Fe(CN)6,  3  H2O  +2  KMnO4  +  8  H2SO4  = 
10  K3Fe(CN)6  +  6  K2SO4  +  2  MnSO4  +  8  H2O  + 
30  H20. 

157.  Calculate  the  percentage  of  carbon  dioxide  in  a 
sample  of  calcium  carbonate  from  the  following  data : 

Total  volume  N/2  HC1  =  35  cc. ;  total  volume  N/10 
NaOH  =  15  cc.  ;  weight  carbonate  =  1.00  g. 

158.  Calculate     the    weight    of    KHC2O4,  C2H2O4, 
2  H2O  necessary  for  a  1.  of  normal  solution,  (a)  as  a 
standard  acid  solution,  (5)  as  a  reducing  agent. 

KHC2O4,  C2H2O4,  2  H2O  +  2  MnO2  +  3  H2SO4  = 
2  MnSO4  +  KHSO4  +  4  CO2  +  4  H2O  +  2  H2O. 

159.  Given  the  following  data,  calculate  the  percent- 
age purity  of  the  oxalic  acid : 

Standardization:  weight  CaCO3=  1.050  g. ;  HC1 
solution  used  =  45  cc. ;  NaOH  solution  used  =4.8  cc.  ; 
1  cc.  NaOH  solution  =  1.042  cc.  HC1  solution. 

Analysis:  weight  oxalic  acid  =  1.500  g.  ;  NaOH 
solution  used  =  42.5  cc. ;  HC1  solution  used  =  0.5  cc. 

160.  Given   the   following    data,  calculate    the   per- 
centage purity  of  the  cream  of  tartar  (KHC4H4O6)  : 


ANALYTICAL  CALCULATIONS  161 

Weight  of  substance  =  2.500  g.  ;  NaOH  solution 
used  =  25.51  cc.  ;  H2SO4  solution  used  =  0.5  cc.  ;  1  cc. 
H2SO4  solution  =  1.02  cc.  NaOH  solution  ;  1  cc.  NaOH 
solution  =  0.0255  g.  CaCO3. 

161.  If    10    cc.    of   a   sulphuric  acid  solution   yield 
0.1220   g.    BaSO4,    how   much   must   the   solution   be 
diluted  for  an  exactly  N/10  solution? 

162.  If  1  cc.  of  a  potassium  bichromate  solution  will 
oxidize  0.0066  g.  of  iron,  to  what  volume  must  100  cc. 
of  the  solution  be  diluted  to  make  a  N/100  solution  ? 

163.  Calculate   the   percentage    of   iron    (Fe)    in   a 
sample  of  limonite  from  the  following  data : 

Weight  of  limonite  =  0.55  g.  ;  K2Cr2O7  solution 
used  =  51.1  cc. ;  1  cc.  K2O2O7  solution  =  0.0058  g.  Fe  ; 
FeSO4  solution  used  =  5  cc. ;  5  cc.  of  FeSO4  solution 
contains  0.008  g.  FeO. 

164.  A  sample  of  iron  wire  is  dissolved,  out  of  con- 
tact with  air,  in  30  cc.  of  HC1,  of  which  1  cc.  =  0.95  cc. 
N/2  HC1.     The  iron  requires  40  cc.    of  N/10  K2Cr2O7 
for  oxidation.     What  excess  of  HC1  was  used  over  that 
required  for  solution  ? 

165.  How  much  stannous  chloride  by  weight  will  be 
required   to   reduce   the   iron   from  0.5   g.  magnetite 
(FeO,  Fe2O3),  dissolved  out  of  contact  with  air  ? 

166.  How   many   cc.    of   HC1    (sp.    gr.  =1.12)  are 
required  to  dissolve  0.55  g.  limonite  (2  Fe2O3,  3  H2O), 
assuming  the  only  impurity  to  be  1.5  %  quartz  ? 

167.  If  0.75  g.  of  a  silicate   yields  0.4  g.  Fe2O3  + 
A12O3,  and  the  iron  present  requires  20  cc.  K2Cr2O7  solu- 
tion [1  cc.  =  0.0784  g.  FeSO4(NH4)2SO4,  6  H2O],  cal- 
culate the  percentage  of  FeO  and  A12O3  in  the  sample. 


162     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

168.  What  weight  of  iron  wire  containing  99.85  %  Fe 
will  react  with  the  chromium  from  0.5  g.  of  chromite 
(FeO,  Cr2O3)  ? 

169.  Calculate  the  value  of  a  permanganate  solution, 
of  which  1  cc.  =  0.008  g.  of  Fe,  in  terms  of  MoO3- 

Mn2O7  +  10  FeO  =  5  Fe2O3  +  2  MiiO  ; 
7  Mn2O7  +  Mo24O37  =  24  MoO3  +  14  MnO. 

170.  Given   the   following   data,  calculate   the   per- 
centage of  iron  in  the  limonite  : 

Weight  of  limonite  =  0.55  g. ;  KMnO4  solution  used 
=  30  cc.  ;  1  cc.  KMnO4  solution  =  0.0084  g.  C2H2O4, 
2  H20. 

171.  The  calcium  oxalate  precipitate  from  0.5  g.  of 
marble,   when   treated   with   sulphuric   acid,    liberates 
sufficient  oxalic  acid  to  reduce  43  cc.  of  permanganate 
solution   (1   cc.  =  0.0115  g.  Fe).     Calculate  the  per- 
centage of  calcium  in  the  marble. 

172.  If  1  cc.  of  KMnO4  solution  will  oxidize  0.008  g. 
iron,   calculate   the    equivalent    of   the    same   solution 
in  terms  of  hydrogen  peroxide,  and  also  the  volume  of 
oxygen  which  will  be  evolved  by  each  cc.  of  the  per- 
manganate solution  during  the  reaction,  assuming  that 
1  cc.  of  oxygen  weighs  0.00143  g.   under  the  existing 
conditions. 

5  H202  +  2  KMn04  +  3  H2SO4  =  K2SO4  +  2  MnSO4  + 
5O2+5H2O. 

173.  Given   the    following   data,  calculate  the   per- 
centage of  MnO2  in  the  pyrolusite  : 

Weight  of  pyrolusite  =  0.48  g.  ;  weight  of  FeSO4, 
(NH4)2SO4,  6  H2O  =  4.3501  g.  ;  K2Cr2O7  solution  used 
=  10  cc. ;  1  cc,  K2Cr2O7  solution  =  0.005  g.  Fe. 


ANALYTICAL  CALCULATIONS  163 

174.  Given  the    following    data,  calculate    the   per- 
centage of  MnO2  in  the  pyrolusite  : 

Weight   of  pyrolusite  =  0.48   g. ;    weight   of  iodine 
liberated  from  KI  =  1.296  g. 

175.  If  1  cc.  iodine  solution  is  equivalent  in  oxidiz- 
ing power   to    0.00149  g.   of  KBrO3,  to  what  volume 
must  100  cc.  be  diluted  to  make  a  N/20  solution  ? 

176.  Calculate  the  percentage  purity  of  the  sample 
of  potassium  dichromate  from  the  following  data : 

Weight    of   sample  =  0.1237    g.  ;   Na2S2O3  solution 
used  =  25  cc. ;  1  cc.  Na2S2O3  solution  =  1.004  cc.  iodine 
solution  ;  1  cc.  iodine  solution  =  0.004975  g.  As2O3. 
K2Cr2O7  +  6  KI  +  7  H2SO4  =  4  K2SO4  +  Cr2(SO4)3  + 
3I2  +  7H20. 

177.  Calculate  the  percentage  purity  of  a  sample  of 
potassium  iodate  from  the  following  data : 

Weight  of  sample  =  0.25  g.  ;  Na2S2O3  solution  used 
=  50  cc. ;  1  cc.  Na2S2O3  solution  =  0.015  g.  I. 

178.  If   1    cc.    of   an   iodine    solution  has  the  same 
oxidizing   power  as  0.0034   g.  of  KIO3,  calculate   its 
value  in  terms  of  antimony. 


CHAPTER  XIII 

Review  —  Systematic  and  Miscellaneous 
SYSTEMATIC  REVIEW 

1.  A  pressure  of  1000  Ib.  per  in.2  is  how  many  Kg. 
per  mm.2? 

2.  When   the   mercury   (sp.  gr.  =  13.59)  barometer 
stands  at  76  cm.,  how  high  will  one  of  glycerine  (sp. 
gr.  =  1.27)  stand? 

3.  When  the  mercury  barometer  stands  at  760  mm., 
how  high  would  one  of  hydrogen  sulphate  (sp.  gr.  = 
1.83)  stand? 

4.  When  the  barometer  stands  at  31  in.,  what  is  it 
in  mm.? 

5.  When  the  barometer  stands  at  755  mm.,  what  is 
it  in  in.? 

6.  When  the  pressure  of  the  air  is  750  mm.  of  mer- 
cury (sp.  gr.  =  13.59),  what  is  it  (0)  in  feet  of  water ; 
(6)  in  Ib.  per  in.2? 

7.  If  200  cc.  of  oxygen  are  measured  off  over  water 
at  +14°  C.  and  756  mm.,  what  does  the  dry  normal  gas 
measure  ? 

8.  How   much   MnO2  is   required   to  make  10  1.  of 
oxygen  ? 

164 


SYSTEMATIC  REVIEW  165 

9.    What  weight  and  volume  of  oxygen  at  +15°  C. 
is  obtained  on  passing  CO2  over  1  Kg.  of  calcium  plum- 
bate  heated  to  redness  and  then  through  slaked  lime? 
Ca2Pb(  )4  +  2  C02  =  2  CaCOg  +  PbO  +  O. 

10.  If   481  g.   of  BaO2  are  heated,  what  volume  of 
oxygen  at  + 17°  C.  and  800  mm.  is  evolved? 

11.  What  would  be  the  volume  of  the  liquefied  gas 
if  the  density  of  it  is  0.89? 

12.  In  an  experiment   the   CuO  lost  59.789  g.  and 
67.282  g.  of  water  was  formed.     Calculate  the  atomic 
weight  of  oxygen. 

13.  What  volume  is  occupied  by  1  g.  of  liquid  hydro- 
gen (sp.  gr.  =  0.07)  ?    If  the  boiling  point  is  -  238.5°  C., 
what  is  it  in  F.°? 

14.  A  balloon  holds  64  m.3  of  hydrogen  ;  how  many 
Kg.  does  the  gas  weigh? 

15.  How  many  1.  of  hydrogen  at  -f  10°  C.  and  770 
mm.  are  obtained  on  passing  2  g.  of  steam  over  red-hot 
iron? 

16.  What  is  the  mass  of  1  1.  of  hydrogen  measured 
over  water  at  +  50°  C.  and  790  mm.  ? 

17.  What  volume   is    occupied  by  100  g.  of  steam 
measured  at  +300°  C.? 

18.  What  is  the  volume  of  1000  g.  of  (a)  sea  water 
(sp.  gr.  =  1.026);   (6)  ice  (sp.  gr.  =  0.92)? 

19.  A  block  of  ice  (sp.  gr.  =  0.92)  weighs  280  Kg.; 
find  its  volume. 

20.  If  the  density  of  ice  is  0.92,  what  volume  will 
1000  cc.  of  water  at  +  4°  C.  occupy  when  frozen? 

21.  An  iceberg  floats  in  sea  water  with  30,000  m.3 
above  the  sea ;  what  is  the  total  volume  of  the  berg  ? 


166     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

22.  If  100  g.  of  gypsum  are  heated,  what  volume  of 
steam  at  +  300°  C.  is  given  off? 

23.  If  88.88  parts  of  oxygen  unite  with  11.11  parts 
of  hydrogen,  and  the  equivalent  of  oxygen  be  100,  what 
is  the  equivalent  of  hydrogen? 

24.  If  500  cc.  of  hydrogen  at  +39°  C.  are  exploded 
with  500  cc.  of  oxygen  under  a  pressure  of  332.5  mm. 
what  volume  of  which  gas  is  left? 

25.  How  much  water  must  be  electrolyzed  to  give  a 
1.  of  gas  at  +  15°  C.  and  740  mm.? 

26.  Find  the  density  of  steam  at  +  300°  C.  referred 
to  air  at  0°  C.     A  Ib.  of  dry  steam  at  +  374°  F.  occu- 
pies how  many  ft.3? 

27.  How  many  g.  does  a  ft.3  of  aqueous  vapor  meas- 
ure at  +  212°  F.  and  30  in.  of  mercury  weigh? 

28.  What  do  100  1.  of  nitrogen  weigh? 

29.  When  100  g.'  of  Pb(NO3)2  were   heated,  they 
were  found  by  Svanberg  to  leave  67.4016  g.  of  PbO. 
If  O  =  100  and  Pb  =  1294,  what  is  the  atomic  weight 
of  nitrogen  ? 

30.  What  volume  is  occupied  by  10,000  g.  of  HNO3 
(sp.gr.  =1.53)? 

31.  What  is  the  least  quantity  of  H2SO4  which  can 
be  used  to  decompose  500  g.  of  KNO3? 

32.  How  much  KNO3  and  what  volume  of  H2SO4  (sp. 
gr.  =1.84)  must  be  distilled  together  to  form  a  1.  of 
HNO3  (sp.  gr.  =  1.53)  ? 

33.  How  many  oz.   of  AgNO3  are  formed   by    the 
action  of  HNO3  (sp.  gr.  =  1.4)  upon  1000  g.  of  Ag? 

34.  How  much  NH4NO3  is  required  to  make  40 1.  of 
N20? 


SYSTEMATIC  REVIEW  167 

35.  What  volume  of  hydrogen  is  required  to  combine 
with  the  oxygen  contained  in  10  g.  of  nitrous  oxide? 

36.  What  volume  of  NO  at  +  13°  C.  is  obtained  on 
dissolving  25  g.  of  Cu  in  HNO3? 

37.  What  volume  of  oxygen  is  required  to  convert 
10  g.  of  NO  in  presence  of  water  into  HNO3? 

2NO  +  H20  +  30  =  2HN03. 

38.  How  many  g.  of  NH3  can  be  obtained  from  2140 
g.  of  NH4C1? 

39.  How  many  g.  of  NH3  are  obtained  on  passing 
3  g.  of  NO,  mixed  with  excess  of  H,  over  hot  spongy 
Pt? 

2  NO  +  10  H  =  2  NH3  +  2  H2O. 

40.  If  2  g.   of  potassium    are  heated  in  NH3,  how 
much  potassamide  and  what  volume  of  H  at  +  15°  C. 
are  formed? 


41.  If  2  1.  of  nitrosyl  chloride  at  +  15°  C.  are  passed 
over  warm  AgNO3,  how  much  N2O5  is  formed? 

NO2C1  +  AgNO3  =  AgCl  +  N2O5. 

42.  If  100  1.  of  air  are  passed  over  red-hot  Cu,  how 
much  does  the  Cu  increase  in  mass? 

43.  If    20   cc.   of  air   are   mixed  with  30  cc.   of   H 
and  exploded,  what  volumes  of  what  gases  are  left? 

44.  What  is  the  difference  in  mass  between  10  1.  of 
air  at  +  15°  C.  and  10  1.  of  N  under  775.62  mm.  ? 

45.  A  man  inhales  18  ft.3  of  air  per  hour.     How 
many  Ib.  of  O  does  he  require  in  24  hr.  ? 

46.  What  is  the  mass  of  500  m.3  of  air  at  +  21°  C.  ? 


168     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

47.  An  inch  of  rainfall  is  how  many  tons  of  water  per 
acre? 

48.  How  much  moist  iron  can  be  oxidized  by  1000  1. 
of  air  at  +  13°  C.  ? 

49.  How  much  S  can  be  burned  in  20  1.  of  air  at  +  26° 
C.? 

50.  What  volume  of  air  at  +  21°  C.  must  be  passed 
over  100  g.  of  Cu  to  convert  it  into  CuO  ? 

51.  How  much  Mg  can  be  burned  in  a  globe  contain- 
ing 5  1.  of  air  at  +21°  C.  and  744  mm.  ? 

52.  A  cubic  mile  of  air  at  760  mm.  and  -f-  30°  C.  is 
saturated  with  water  vapor.     How  many  tons  of  rain 
will  fall  if  the  temperature  sinks  to  0°  C.  ? 

53.  In  one  of  Lord  Rayleigh's  experiments,  7925  cc. 
of  air  left  65  cc.  of  argon ;  what  is  the  percentage  by 
volume  of  argon  in  the  atmosphere? 

54.  The  specific  heat  of  graphite  is  0.202;  what  is 
its  probable  atomic  weight? 

55.  If  4427  million  ft.3  of  coal  are  piled  into  a  cube, 
find  the  length  of  each  edge  in  m. 

56.  Find   the    formula   of   a   substance   containing: 

0,20%;  0,26.6%;   8,53.3%. 

57.  What  volume  of  air  is  required  to  burn  a  Kg.  of 
carbon  ? 

58.  If  15.2  1.  of  methane  at  -f  17°  C.  and  870  mm.  are 
required,  how  much  dry  sodium  acetate  must  be  used? 

59.  If  25  cc.  of  ethene  are  exploded  with  100  cc.  of 
O,  what  volume  of  CO2  is  formed  and  of  O  is  left? 

60.  What  volume  of  cyanogen  at  + 16°  C.  is  given 
off  on  heating  5  g.  of  Hg(CN)2? 


SYSTEMATIC   REVIEW  169 

61.  Find  the  mass  of  295  cc.  of  camphor  (C10H16O) 
vapor  at  +  210°  C. 

62.  In  Meyer's  third  method,  0.12  g.  of  dibromamy- 
lene  gave    13.1  cc.  of   air  at   + 17°  C.  and    758  mm. 
Find  the  density  of  the  vapor. 

63.  How  many  g.  of  MnO2   are  required   to  make 
40  1.  of  Cl  at  +  37°  C.  ? 

64.  What  volume  of  Cl  at  +  12°  C.  and  750  mm. 
can  be  obtained  from  1170  g.  of  salt? 

65.  If  10  g.  of  K2Cr2O7  are  heated  with  HC1,  what 
volume  of  Cl  at  +  30°  C.  and  740  mm.  is  given  off? 

K2Cr2O7  +  14  HC1  =  7  H2O  +  2  KC1  +  2  CrCl3  +  3  C12. 

66.  What  volume  of  Cl  will  diffuse  under  the  same 
conditions  as  10  cc.  of  N  ? 

67.  When  1  g.  of  bleaching  powder  was  boiled  with 
CuO,    it  gave    80  cc.  of  O  at   +  7°  C.  and   800  mm. 
Find  the  percentage  of  real  bleaching  powder  in  the 
sample. 

68.  What  is  the  mass  of  1  1.  of   chloroform  vapor 
measured  at  +  200°  C.  ? 

69.  How  many  cc.  does  a  Ib.  of  Br  (sp.  gr.  =  3.19) 
occupy  ? 

70.  How  much  P  and  what  volume  of  Br  is  required 
to  make  1  1.  of  HBr  ? 

P  +  3  Br  +  3  H2O  =  H3PO4  +  3  HBr. 

71.  Br  vapor  is  2.8  times  as  heavy  as  air  ;  what  is  its 
molecular  weight? 

72.  If  10  g.  of  KBrO3  are  heated,  what  volume  of 
oxygen  measured  at  +  13°  C.  is  given  off  ? 

73.  A  spherical  glass  bulb  contains  10  g.  of  liquid 
Br  (sp.  gr.  =  3.19) ;  what  must  the  internal  radius  be  ? 


170     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

74.  How  much  FeCl3  is  required   to   obtain  iodine 
from  100  tons  of  kelp,  each  ton  of  which  contains  4.07 
Kg.  of  iodine  ? 

2  Nal  +  2  FeCl8  =  2  NaCl  +  2  FeCl2  +  I2. 

75.  How  many  times  is  solid  iodine  (sp.  gr.  =  4.94) 
as  heavy  as  an  equal  volume  of  its  vapor  measured  at 
+  350°  C.  ? 

76.  How  much  iodine  is  there  in  a  1.  of  a  solution 
(sp.  gr.  =  1.7)  containing  52%  of  HI? 

77.  How  much  iodine  and    KC1O3  are  required  to 
make  1  Kg.  of  hydrogen  iodate  ? 

10  KC1O3  +  12  I  +  6  H2O  =  10  KC1  +  12  HIO3. 

78.  If  8  g.  of  silver  iodate  are  heated,  what  volume 
of  oxygen  at  + 18°  C.  and  720  mm.  is  evolved? 

79.  What  volume  of  HF  at  +  39°  C.  can  be  obtained 
from  50  g.  of  NaF? 

80.  Find  the  mass  of  10  1.  of  HF  at   +  30°  C.  and 
740  mm. 

81.  What   volume   is  occupied   by  1000   g.    of    (a) 
common  sulphur  (sp.  gr.  =  2.05),  (6)  plastic  sulphur 
(sp.  gr.  =  1.95)? 

82.  What  volume  is  occupied  by  19.2  g.  of  SO2? 

83.  If  16  cc.  of  H  diffuse  in  100  sec.,  what  volume 
of  SO2  will  diffuse  under  the  same  conditions? 

84.  How  much  iodine  is  needed  to  oxidize  1  g.  of 
"  hypo,"  and  how  much  sodium  tetrathionate  is  formed  ? 

2  Na2S203,  5  H20  +  T2  =  2  Nal  +  10  H2O  +  Na2S4O6. 

85.  SO3  is  passed  over  187  g.  of  BaO  in  a  heated 
tube ;  how  much  BaSO4  is  formed? 


SYSTEMATIC   REVIEW  171 

86.  How  many  Kg.   of  H2SO4(sp.   gr.  =1.84)  will 
a  tank  1  m.  x  2  m.  x  3  m.  hold  ? 

87.  If  100  g.   of  Pb  form  146.45  g.  of  PbSO4,  what 
is  the  molecular  weight  of  H2SO4  ? 

88.  If  20  g.  of  S  are  heated  in  H,  what  volume  of 
H2S  at  +  30°  C.  is  formed? 

89.  If  390  g.  of  Sb2S3  are  dissolved  in  hot  HC1,  what 
volume  of  H2S  at  +  30°  C.  is  given  off  ? 

90.  How  many  g.  of  S  are  there  in  600  ec.  of  H2S  ? 

91.  What  volume  of  H2S  will  diffuse  under  the  same 
conditions  as  10  cc.  of  oxygen  ? 

92.  How  much  PbS  and  HgS  can  be  thrown  down 
by  500  cc.  of  H2S  at  + 14°  C.  ? 

93.  What  volume  of  CS2  (sp.    gr.  =1.26)    can   be 
made  by  the  action  of  a  Kg.  of  S  upon  hot  charcoal? 

94.  What  is  the  mass  of  4  1.  of  carbon  oxysulphide 
(COS)  at  +  30°C.  ? 

95.  To  make  1000  Kg.  of  H2SO4,  how  much  pyrite  is 
needed  ?     What  volume   of   air   at    + 15°  C.    and   of 
steam  at  +  300°  C.  are  required  ? 

2  FeS2  +  4  H20  +  15  O  =  Fe2O3  +  4  H2SO4. 

96.  What  volume  of  CS2  (sp.  gr.  =1.26)  must  be 
burned  to  give  101.  of  SO2  at  +  15°  C.  and  750  mm.? 

97.  Boron  trichloride  is  4.07  times  as  heavy  as  air; 
what  is  its  molecular  weight  ? 

98.  How  many  g.  do  200  cc.  of  BC13  at  +  97°  C.  and 
720  mm.  weigh? 

99.  If    90  g.   of   CaF2  are   heated  with  B2O3  and 
H2SO4,  what  volume  of  BF3  at  +  15°  C.  is  formed  ? 

3  CaF2  +  B203  +  3  H2SO4  =  3  CaSO4  +  3  H2O  +  2  BF3. 


172     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

100.  How  much  Si  can  be  obtained  from  119  g.  of 
K2SiF6  ?     K2SiF6  +  4  K  =  6  KF  +  Si.  i 

101.  How  much  silica  is  formed  on  burning  2  1.  of 
SiH4? 

102.  What  volume  of  Cl.  at  +  26°  C.  and  mass  of  0 
are  required  to  make  100  g.  of  SiCl4  ? 

Si02  +  2  C  +  2  C12  =  2  CO  +  SiCl4. 

103.  How   much   does   a   1.    of   SiCl4  at    +  200°C. 
weigh? 

104.  Find    the    mass    in   g.   of   a   sphere    of   quartz 
(sp.  gr.  =  2.65)  1  dm.  in  diameter. 

105.  How    much     bone     ash     containing     87%     of 
Ca3(PO4)2  is  required  to  make  200  Kg.  of  superphos- 
phate of  lime? 

Ca3(P04)2  +  2  H2S04  =  2  CaSO4  +  CaH4(PO4)2. 

106.  If    100  1.   of   yellow  (sp.  gr.  =  1.83)  are  con- 
verted  into   red  (sp.  gr.  =  2.16)  phosphorus,  what  is 
the  volume  of  the  latter  variety  ? 

107.  What  is  the  mass  of  1.234  1.  of  P  vapor  (P4) 
at  +  500°  C.  ? 

108.  If  1  g.  of  P,  when  burned,  gives  2.29  g.  of  P2O5, 
what  is  the  atomic  weight  of  P? 

109.  Find  the  formula  of   a   substance  containing  : 
Ca,  38.72%;  P,  20%;  O,  41.28%. 

110.  If  20  g.  of  hydrogen  metaphosphate  are  boiled 
with  water,  how  much  orthophosphate  is  formed  ? 

HP03  +  H20  =  H3P04. 

111.  If  5  g.   of   phosphorus  are  boiled  with  baryta 
water,  what  volume  of  PH3  at  +  15°  C.  is  given  off  ? 

2  P4  +  3  Ba(OH)2  +  6  H2O  =  3  Ba  (PH2O2)2  +  2  PH3. 


SYSTEMATIC   REVIEW  173 

112.  What  volume  of  PHg  will  diffuse   under   the 
same  conditions  as  100  cc.  of  hydrogen  ? 

113.  What  volume  of  Cl  at  +  20°  C.  must  be  passed 
into  1  Kg.  of  melted  P  to  convert  it  into  PC18  ? 

114.  How  much  P  is  contained  in  4.3  1.  of  PH3  meas- 
ured at  +  22°  C.  and  730  mm.  ? 

115.  How  many  g.  do  2  1.  of  As4  vapor  weigh  ? 

lie.    If  743  cc.  of  gas  are  heated  from  +47°  C.  to 
-f-  83°  C.,  what  is  the  new  volume  ? 

117.  What  volume  do  486  cc.  of  gas  under  a  pressure 
of  760  mm.    occupy  under   the   pressure    of   3   ft.   of 
mercury  ? 

118.  If  1000  cc.  of  air  at  -31.2°  R.  are  heated  to 
+ 172.4°  F.,  what  is  the  new  volume? 

119.  If  546  cc.  of  gas  at  + 17°  C.  and  760  mm.  are 
cooled  to  0°  C.,  the  pressure  being  decreased  to  600 
mm.,  what  is  the  new  volume  ? 

120.  If  1234  cc.  of  normal  gas  are  cooled  to  —  52°  C., 
the  pressure  being  decreased  to  617  mm.,  what  is  the 
new  volume  ? 

121.  A  few  drops  of  water  at  + 15°  C.  are  passed 
up  into  a  barometer  standing  at  30  in.     How  high  does 
the  mercury  stand  ? 

122.  If  100  g.  pf  Sb  gave  124.8  g.  of  Sb2O4,  and  if 
O  =  100,  what  is  the  atomic  weight  of  Sb  ? 

123.  Bi   melts   at   +  264°  C ;    what   temperature   is 
this  on  the  F.  and  R.  scales  ? 

124.  Schneider  found  that  54.969  g.  of  Bi  formed 
61.311  g.  of  the  trioxide ;  what  is  the  atomic  weight 
of  Bi  ? 


174     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

125.  What  volume  is  occupied  by  10  g.  of  trimethyl- 
stibine  Sb(CH3)3  at  +  300°  C.? 

126.  What  is  the  mass  of  a  sphere  of  Bi  (sp.  gr.  =  9.9) 
2  mm.  in  diameter  ? 

127.  Find  the  volume  of  100  g.  of  (a)  Pt  (sp.  gr. 
=  21.5);    (6)  Au    (sp.    gr.  =19.3);    (c)   Pb   (sp.  gr. 
=  11.4);   (d)  Li  (sp.gr.  =  0.59). 

128.  What  length  of  wire  2  mm.  in  diameter  can  be 
drawn  from  1  dm.3  of  metal  ? 

129.  How  much  platinum  black  is  obtained  on  boil- 
ing 40  g.  of  platinic  chloride  with  grape  sugar  and 
sodium  carbonate  ? 

PtCl4  +  2  Na2C03  =  4  NaCl  +  2  CO2  +  O2  +  Pt. 

130.  If  900  g.  of  Au  (sp.  gr.  =  19.3)  are  fused  with 
100  g.  of  Ag  (sp.  gr.  =  10.5),  what  is  the  density  of 
the  alloy? 

131.  If  5  g.  of  K2O4  are  boiled  with  water,  what  vol- 
ume of  O  at  +  100°  C.  is  evolved  ? 

K204  +  H20  =  2  KOH  +30. 

132.  If  2  g.  of  hydroxylamine  are  heated  with  KOH, 
what  volumes  of  N  and  of  NH3  at  4-  21°  C.  are  formed  ? 

3  NOH3  =  N2  +  NH3  +  3  H2O. 

133.  How  much  SrO  is  obtained  on  heating  1000  g. 
ofSr(N03)2? 

134.  One  g.  of  CaSO4  will  form  how  much  BaSO4  ? 

135.  How  much  Al  is  set  free  on  passing  '7. 339  1.  of 
the  vapor  of  A1C13  at  +  546°  C.  over  heated  Na  ? 

2  A1C13  +  6  Na  =  6  NaCl  +  A12. 

136.  How  much  sulphide  is  formed  on  heating  5  g. 
of  Al  in  S  vapor  ? 


SYSTEMATIC  REVIEW  175 

137.  If  20  g.  of  cryolite  are  heated  with  H2SO4,  what 
volume  of  HF  at  +  20°  C.  is  given  off  ? 

2  Na8AlF6  +  6  H2SO4  =  3  Na2SO4  +  A12(SO4)3  +  12  HF. 

138.  If  4  g.  of  dolomite,  when  strongly  heated,  gave 
937.4  cc.  of  CO2,  what  is  the  percentage  of  Ca  and 
MgCO3  in  the  dolomite  ? 

(CaMg)C03  =  (CaMg)O  +  CO2. 

139.  What  volume  of  N  at   -h  20°  C.  and  780  mm. 
will  combine  with  50  g.  of  Mg  ? 

140.  How  much  zinc  white  can  be  made  from  1000  g. 
of  Zn  and  what  volume  of  air  is  required  ? 

141.  Brass  consists  of  2  parts  of  Cu  alloyed  with 
1  part  of  Zn ;  find  the  approximate  formula  for  it. 

142.  If  100  g.  of  sodium  manganate  are  heated  in 
steam,  what  volume  of  oxygen  at  -h  13°  C.  is  set  free  ? 

Na2MnO4  +  H2O  =  2  NaOH  +  MnO2  +  O. 

143.  During  the  solution  of  1  g.  of  iron,  389.74  cc. 
of  H  at  + 14°  C.  and  820  mm.  were  evolved ;  find  the 
equivalent  of  iron. 

144.  According  to   Berzelius,   1.586  g.  of  Fe  form 
2.265  g.  ferric  oxide;    what   is  the  atomic  weight  of 
iron  ? 

145.  What  volume  of  CO  at  + 17°  C.  is  set  free  on 
heating  10  g.  of  diferroheptacarbonyl  to  +  80°  C.  ? 

Fe2(CO)7  =  Fe  +  Fe(CO)5  +  2  CO. 

146.  How  much  S  precipitates  on  passing  1.7  1.  of 
H2S  at  +  17°  C.  through  a  solution  of  FeCl3? 

2  FeCl3  +  H2S  =  2  FeCL  +  2  HC1  +  S. 


176     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

147.  How  much  Fe  is  converted  from  a  ferrous  to 
a  ferric  salt  by  1  g.  of  potassium  (a)  permanganate ; 
(5)  dichromate  ? 

10  FeSO4  +  2  KMnO4  +  8  H2SO4  = 

5  Fe2(SO4)3  +  K2SO4  +  MnSO4  +  8  H2O  ; 
6  FeSO4  +  K2Cr2O7  +  7  H2SO4  = 

3  Fe2(S04)3  +  K2S04  +  Cr2(SO4)3  +  7  H2O. 

148.  If  3  g.  of  KMnO4  and  K2Cr2O7  are  each  dis- 
solved in  1  1.  of  water,  to  how  much  Fe  is  1  cc.  of  each 
solution  equivalent  ? 

149.  What  volume  of  CO  at  +  1200°  C.  is  set  free  in 
reducing  764  g.  of  nickelous  oxide  ? 

NiO  +  C  =  Ni  +  CO. 

150.  How  much  HgO  is  required  to  precipitate  20  g. 
of  Ni  as  NiO  ? 

NiCl2  +  HgO  =  HgCl2  +  NiO. 

151.  What  is  the  formula  of  a  substance  containing : 
Ni,    31.15%;  H,    3.18  %;    N,   14.84%;     S,  16.95%; 
O,  33.88%?  . 

152.  What  volume  of  H  at  + 15°  C.  is  required  to 
reduce  100  g.  of  Co2O3? 

153.  If  100  g.    of  Hg2CrO4  are  heated,  how  much 
Cr2O3  is  formed  and  what  volume  of  O  is  given  off? 

2  Hg2Cr04  =  4  Hg  +  Cr2O3  +  5  O. 

154.  According  to    Siewert,   36.865  parts  of   CrCl3 
give  100  parts  AgCl ;  find  the  atomic  weight  of  chro- 
mium. 

155.  How  much    (NH4)2Cr2O7  can   be   made  from 
1000  g.  of  K2Cr207  ? 

K2Cr207  +  H2S04  =  K2S04  +  H2O  +  2  CrO3 ; 
2  Cr03  +  2  NH3  +  H2O  =  (NH4)2Cr2O7. 


SYSTEMATIC  REVIEW  177 

156.  According  to  Berlin,  100  g.  of  Pb(NO3)2  gave 
97.576  g.  of  PbCrO4;  find  the  atomic  weight  of  chro- 
mium. 

157.  What  volume  of  SO2  at  + 15°  C.  and  780  mm. 
is  required  to  reduce  47  g.  of  K2Cr2O7? 

K2Cr207  +  3S02  +  H2S04  =  Cr2(SO4)3  +  KaSO4+  H2O. 

158.  How  many  times  is  the  vapor  of  chromyl  dichlo- 
ride  (CrO2Cl2)  as  heavy  as  air  ? 

159.  If  17  g.  of  Sn  were  dissolved  in  NaOH,  what 
volume  of  H  at  -f- 15°  C.  was  evolved  ? 

Sn  +  2  NaOH  +  H2O  =  Na2SnO3  +  2  H2. 

160.  What  volume  of  HC1  at  +  60°  C.  is  required  to 
convert  50  g.  of  Sn  into  stannous  chloride? 

161.  What  volume  of  Cl  at  +  26°  C.  is  absorbed  in 
converting  1000  g.  of  Sn  into  the  tetrachloride? 

162.  What  volume  of  H2S  at  +  26°  C.  is  required  to 
throw  down  the  Sn  from  a  solution  of  110  g.  of  "  tin 
salts"? 

SnCl2,  2  H20  +  H2S  =  SnS  +  2  HC1  +  2  H2O. 

163.  If  9  g.  of  Sn  are  dissolved  in  aqua  regia,  what 
volume  of  H2S  at  +  15°  C.  and  770  mm.  is  required  to 
precipitate  them? 

164.  If  4  g.  of  Sn  are  heated  in  200  cc.  of  H2S  at 
+ 10°  C.  and  744  mm.,  how  much  does  the  Sn  increase 
in  mass  ? 

165.  What  volume  of  air  is  required  to  convert  37.1 
Kg.  of  Pb  into  litharge? 

166.  How  much  silica  must  be  fused  with  1000  g.  of 
PbO  to  form  lead  silicate  ? 


178     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

167.  What  volume  of  O  at   + 13°  C.  is  absorbed  in 
forming  1000  g.  of  red  lead? 

168.  According  to  Dumas,  100  g.  of  minium  when 
heated  give  2.4  g.  of  O;  find  its  formula. 

169.  Find   the  percentage    composition    of   realgar, 
orpiment,  and  arsenic  pentasulphide. 

170.  What  volume  of  H2S  at  +  21°  C.  is  required  to 
precipitate  the  As  from  a  solution  of  100  g.  of  As2O3? 

171.  The  specific  heat   of  As  is  0.0814  and   96.15 
parts  of  As  combine  with  3.85  parts  of  H;    find  the 
atomic  weight  of  the  element. 

172.  How  much  Sb  is  there  in  1020  Kg.  of  the  tri- 
sulphide  ? 

173.  What  volume  is  occupied  by  100  g.  of  (a)  As 
(sp.  gr.  =  5.8) ;  (6)  Sb  (sp.  gr.  =  6.8) ;  <»  Bi  (sp.  gr.  = 
9.9)? 

174.  How  much  lead  dioxide  can  be  made  from  20  g. 
of  Pb(N03)2? 

Pb(N03)2  +  CaOCl2  +  H20  =  2  HC1  +  Ca(NO3)2  +  PbO2. 

175.  Find  the  formula  of  Cassel  yellow,  which  con- 
tains: Pb,  90.05%;  Cl,  3.86%;  and  O,  6.09%. 

176.  PbI2  is  soluble  in  190  times  its  mass  of  hot  water. 
How  much  KI  and   Pb(NO3)2  must  be   dissolved  in 
250  cc.  of  water  that  the  precipitate  may  redissolve  on 
boiling  ? 

177.  According  to  Stas,  100  g.  of  Pb  form  195. 9703  g. 
of  Pb(NO3)2;  what  is  the  atomic  weight  of  Pb? 

178.  A  substance  contains  of  lead  monoxide  76.69% 
and  of  chromium  trioxide  23.31%  ;  find  its  formula. 


SYSTEMATIC  REVIEW  179 

179.  What  volume  of  CO2  at  -f  26°  C.  is  evolved  on 
dissolving  487  g.  of  white  lead  in  hydrogen  nitrate? 

Pb(OH)2,  2  PbC03  +  6  HN03  = 
4H20  +  3Pb(N03)2  +  2C02. 

180.  What  volume  is  occupied  by  the  vapor  of  4  g. 
plumbic  ethide,  Pb(C2H5)4,  measured  at  +  300°  C.  and 
740  mm.? 

181.  If  100  g.  of  CuSO4  are  warmed  with  KOH  and 
grape  sugar,  how  much  cuprous  oxide  precipitates? 

2  CuSO4,  5  H2O  +  4  KOH  = 
2  K2SO4  +  12  H2O  +  O  +  Cu2O. 

182.  What  volume  of  H  at  +  100°  C.  and  746  mm. 
is  given  off  on  dissolving  3  g.  of  cuprous  hydride  in 
HC1? 

Cu2H2  +  2  HC1  =  Cu2Cl2  +  2  H2. 

183.  If  8000  g.  of  cinnabar  are  roasted,  how  much 
Hg  and  what  volume  of  SO2  at  + 13°  C.  are  formed? 

184.  Hg  vapor  is  6.976  times  as  heavy  as  air;  find 
its  density  referred  to  H. 

185.  When  1  Kg  of  Hg  at  -f  100°  C.  is  mixed  with 
1   Kg  of  water  at    -f  10°  C.,   the  temperature  of  the 
mixture  was  found  to  be  + 13°  C.;  what  is  the  specific 
heat  of  Hg? 

186.  Find  the  formula  of  a  cadmium  amalgam  which 
contains  :   Hg,  78.26  %,  and  Cd,  21.74%. 

187.  Excess  of  Hg  is  heated  in  10  1.  of  air  measured 
at  +  14°  C.  ;  how  much  HgO  is  formed  ? 

188.  The  vapor  of  Hg2Cl2  is  8.21  times  as  heavy  as 
air;   what  is  its  apparent  molecular  weight? 

189.  How  many  g.  do  500  cc.  of  the  vapor  of  corro- 
sive sublimate  at  -h  350°  C.  weigh? 


180     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

190.  How  much  Fe  and  Hg  are  required  to  reduce 
48  Ib.  of  AgCl? 

191.  Melted   Ag   dissolves    22   times  its  volume    of 
oxygen  at  0°  C.     What  volume  of  O  at  +  13°  C.  would 
be  given  off  by  1  Kg.  of  Ag  (sp.  gr.  =  10.5)  on  cool- 
ing? 

192.  According    to    Stas,    53.1958   g.    of   Ag    form 
92.6042  g.    of   AgBr;    what  is  the  atomic  weight  of 
silver  ? 

193.  What  volume  of  H2S  at  +  27°  C.  and  570  mm. 
is  required  to  precipitate  the  Ag  from  100  g.  of  silver 
metaphosphate  ? 

2  AgP08  +  H2S  =  Ag2S  +  2  HP03. 

194.  How   much  FeSO4   is   required   to   precipitate 
100  g.  of  Au? 

6  FeS04,  7  H20  +  2  AuCl3  = 
4  Fe2(SO4)3  +  42  H2O  +  2  FeCl3  +  2  Au. 

195.  How  much  magnesia  is  required  to  throw  down 
10  g.  of  auric  oxide  ? 

2  AuCl3  +  3  MgO  =  3  MgCl2  +  Au2O3. 

196.  What   volume   of    O    is   given   off   on  heating 
4.412  g.  of  Au2O3? 

197.  Prat  has  described  an  oxide  of  gold  containing 
7.7%  of  oxygen;  find  its  formula. 

198.  How  much  aurous  bromide  can  be  made  from 
2  g.  of  Au2O  ? 

199.  If  50  g.  of  auric  chloride  are  heated  to  +  170°  C., 
how   much   aurous   chloride   and   what  volume    of    Cl 
measured  at  +  21°  C.  are  formed? 

AuCL  =  AuCl  +  CL. 


SYSTEMATIC  REVIEW  181 

200.  A  solution  of  10  g.  of  AuCl3  is  mixed  with  hy- 
drogen oxalate ;  how  much  Au  precipitates  and  what 
volume  of  CO2  at  +  13°  C.  is  given  off? 

2  AuCl3  +  3  H2C2O4  =  2  Au  +  6  HC1  +  6  CO2. 

201.  How  much  spongy  platinum  is  left  on  heating 
100  g.  (NH4)2Pt018? 

202.  How  much  PtCl4  is  obtained  on  dissolving  500  g. 
of  Pt  in  aqua  regia? 

203.  How  much  platinous  hydrate  is  formed  on  di- 
gesting 200  g.  of  platinous  chloride  with  KOH? 

PtCl2  +  2  KOH  =  2  KC1  +  Pt(OH)2. 

204.  According    to    Berzelius,    10  g.     of    Pt    form 
24.735    g.    of    K2PtCl6;    find    the    atomic   weight    of 
platinum. 

MISCELLANEOUS  REVIEW 

205.  How    much    CaO    and    how    much    coke    are 
needed  to  produce  100  Ib.  of  CaC2? 

206.  How  much  chrome-alum  could  be  made  from 
10  Kg.  of  chromite? 

207.  What  weight  of  chrome-yellow  would  be  formed 
if  a  solution  containing  430  g.  of  K2CrO4  were  precipi- 
tated with  lead  acetate  ? 

208.  What  weight  of  KMnO4  could  be  prepared  from 
10  Kg.  of  an  ore  containing  62  %  pyrolusite  ? 

209.  Find  the  percentage  composition  of  nitric  acid. 
How  many  g.  of  each  component  in  150  g.  of  nitric 
acid? 

210.  Find    the    percentage    composition    of   H2SO4. 
How  many  g.  of  HC1  can  be  formed  by  the  action  of 
490  g.  of  H2SO4onNaCl? 


182     PROGRESSIVE  PROBLEMS  IN  CHEMISTRY 

211.  Find  the  percentage  composition  of  H2S.     How 
many  g.  of  H2S  can  be  made  by  the  action  of  146  g.  of 
HC1  on  ferrous  sulphide? 

212.  A  mixture  of  30  cc.  of  air  and  40  cc.  of   hy- 
drogen is  introduced  into  a  eudiometer  tube  and  the 
mixture  ignited  by  an  electric  spark.     The  gas  remain- 
ing in  the  tube  after  the  explosion  measures  51.1  cc. 
What  per  cent,  by  volume  of  oxygen  is  contained  in 
the  air  used,  assuming  that  the  gases  are  all  measured 
at  the  same  temperature? 

213.  A  candle  of  paraffine  (C,  85  %  ;  H,  15  %  )  loses 
90  g.   in  weight  by  burning ;    find   the    weights   and 
volumes  of  the  products  of  combustion  and  of  oxygen 
used. 

214.  What  weight  of  phosphorus  would  be  needed  to 
combine  with  700   cc.  of  oxygen  to  form  phosphorus 
pentoxide? 

215.  If    1  g.  of  hydrogen  and  1    g.    of  oxygen  are 
mixed  and  the  mixture  is  ignited,  what  weight  of  water 
will  be  formed  and   what  volume   of  gas  will  remain 
uncombined  ? 

216.  What  weight  of  oxygen  will  unite  to  form  water 
with  a  volume   of   hydrogen  that  measures  1250  cc.  at 
740mm.  and  +18°C.? 

N  217.  A  certain  analysis  gives  42.1%  of  carbon,  7.1  % 
of  hydrogen,  56.2%  of  oxygen,  (a)  Find  a  formula 
for  the  compound.  (5)  It  being  hexabasic,  give  the 
true  formula.  (<?)  All  the  hydrogen  can  be  replaced  by 
a  metal.  To  what  class  of  compounds  does  it  belong? 
218.  Reduce  the  following  to  the  Fahrenheit  scale  : 
(a)  +35°C.  ;  (5)  +  89°  C.  ;  <V)  -40°  C.  ;  (d)  -50° 
C.  ;  0)  +  104°  C. 


SYSTEMATIC  REVIEW  183 

219.  If  a  given  weight  of  gas  occupies  1.1  1.  at  0°  C. 
and  380  mm.,  what  volume  should  it  occupy  at  +  273° 
C.  and  760  mm.  ? 

220.  Reduce  the  following  to  ft.3  or  in.3  :   (a)  1.5  1. ; 
(6)  760  cc.  ;    (c)  7  m.3  ;    (d)  85  dm.3  ;    <»  900  cc.  ; 
(/)  1.2  cc. 

221.  If  water  absorbs  1000  times  its  volume  of  am- 
monia, how  many  g.  of  ammonium  chloride  will  furnish 
enough  gas  for  2  1.  of  water  ? 

222.  How  many  g.  of  coin  silver,  which  is  T9^  pure, 
will   make    50    g.    of   bromide    of   silver   for    photog- 
raphy ? 

223.  Prove  that  the  phosphorus  molecule  has  4  atoms. 

224.  A  m.3  of  carbon  monoxide  burns  in  air.    (a)  Find 
the  number  of  cc.  of  carbon  dioxide  which  will  form  at 
N.T.P.     (5)  Find  approximately  the  number  of  ft.3 

225.  A  cube  of  sulphur  (sp.  gr.  =  2)  is  2|  cm.  on  a 
side ;  how  much  SO2,  by  weight  and  by  volume,  will 
form  on  burning  it  ? 

226.  By  using  100  tons  of  FeS2  there  were  obtained 
136.3  tons  of  H2SO4.     If  there  were  no  waste,  what  per 
cent,  of  sulphur  does  the  pyrite  carry  ?    What  per  cent, 
does  pure  FeS2  carry  ? 

227.  A  mixture  of  |  hydrogen  by  volume  and  J  arsine, 
5  1.  in  all,  is  burned,     (a)  What   weight   of  water   is 
formed  ?     (£)  What  volume  would  the  arsenic  occupy 
at  -f  273°  C.  if  it  could  be  set  free  as  a  gas  ? 

228.  H2SO4  has  sp.  gr.  =1.84;  what  volume  of  sul- 
phur dioxide  at  +  200°  C.  and  700  mm.  will  be  given  by 
30  cc.  of  it  reduced  by  copper  ? 


184    PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

229.  What  volume  of  hydrogen  is  required  to  combine 
with  the  oxygen  in  12  g.  of  nitrous  oxide  ? 

230.  Water  will  absorb  1050  times  its  volume  of  am- 
monia gas ;  how  many  g.  of  ammonium  chloride  will 
be  required  to  furnish  the  gas  sufficient  to  saturate  500 
cc.  of  water  ? 

231.  If  10  1.  of  hydrogen  diffuse  through  a  certain 
apparatus  in  a  certain  time,  what  volume  of  hydrogen 
phosphide  will  diffuse  under  similar  conditions  ? 

232.  Compute  the  vapor  density  (a)    of  ozone  from 
the  atomic  weight  of  oxygen  and  the  fact  of  there  being 

3  atoms  in  the  molecule  of  ozone  ;    (5)  of  arsenic  with 

4  atoms  per  molecule  ;   (<?)  of  zinc,  which  has  1  atom  per 
molecule. 

233.  A  block  of  lead  (sp.  gr.  =  11.4)  5x2x2  cm. 
is  dissolved  by  HNO3 ;  how  much  NO  by  volume  ought 
to  be  liberated  ? 

234.  How  much  CaCO3  by  weight  should  be  formed 
by  introducing  into  lime  water  the  carbon  dioxide  formed 
in  burning  500  cc.   of   liquid  ether  having  sp.    gr.  = 
0.72? 

235.  How  much  phosphorus  by  weight  can  be  burned 
in  5  1.  of  nitrogen  monoxide  ? 

236.  How  much  H2S  by  volume  will  be  formed  by  the 
action  on  FeS   of  1  1.  of  HC1  solution  which  has  sp. 
gr.  =  1.2  and  contains  43%  HC1  gas  ? 

237.  A  substance  analyzed  gives  20%  water,  26.66% 
carbon,  53.13%  oxygen;  find  its  formula. 

238.  How  much  chlorine  in  a  1.  of  water,   20  cc.    of 
which  will  precipitate  all  the  silver  in  0.02  g.  of  silver 
nitrate  ? 


SYSTEMATIC  REVIEW  185 

239.  If  2  Kg.  of  coal  produce  in  burning  6  Kg.  of  CO2 
and  900  g.  of  water,  what  percentage  of  carbon  and  of 
hydrogen  does  the  coal  contain  ? 

240.  One  g.    of   an    aqueous   solution  of   hydrogen 
chloride  (sp.  gr.  =  1.20)    contains    how  many  cc.   of 
hydrogen  chloride  ? 

241.  How  many  Kg.  in  3  m.3  of  sulphuric  acid  (sp. 


242.  What  volume  would  be  occupied  by  2  cc.  of  sul- 
phuric ether  (sp.  gr.  =  0.72)  if  it  were  vaporized  at 
+  270°  C.  and  750  mm.  ? 

243.  Reduce  the  following  to  C.°  :     (a)    +  38°   F.  ; 
(6)  +  120°  F.  ;  (<0  -64°  F.  ;  (d)  -  30°  F.  ;  (e)  0°  F.  ; 


244.  If  equal  volumes  of  hydrogen  and  oxygen  are 
mixed   in   a  closed  space  at  a  temperature  above  the 
boiling   point  of  water,  and  the  mixture  is  exploded, 
what  will   be  the  pressure  of  the  products  compared 
with  the  original  pressure  at  the  same  temperature  ? 

245.  When  37.4  g.  of  nickel  oxide  were  heated  in  a 
current  of  hydrogen  they  lost  in  weight  8.000  g.     The 
specific  heat  of  nickel  is  0.109.     What  information  do 
these  data  give  concerning  the  atomic  weight  of  nickel  ? 

246.  Write  the  equations  representing   the  volume 
relations,  (a)  when  carbon  monoxide  burns  in  oxygen  ; 
(5)  when  ammonia  gas  is  decomposed  into  its  elements. 
Give  the  relative  numbers  of  molecules  taking  part  in 
each  reaction  . 

247.  What  volume  is  occupied  by  80  g.  of  ammonia 
(a)   at   N.T.P.;    (b)  at   +273°  C.  and  pressure  of  2 
atmospheres  ? 


186     PROGRESSIVE   PROBLEMS  IN   CHEMISTRY 

248.  How  much  ammonium  chloride  must  be  heated 
with  lime  to  make  50  1.  of  ammonia  at  N.T.P.  ? 

249.  Write  equations  for  (a)  the  action  which  takes 
place  on  boiling  water  hardened  by  carbonate  of  mag- 
nesium in  solution ;   (6)  the  preparation  of  peroxide  of 
hydrogen;   (<?)  the  action  of  carbonic  acid  on  barium 
hydrate. 

250.  How   much   zinc    sulphate    can   be  made  from 
20  Ib.  of  zinc  ? 

251.  If  3  1.  of  a  gas  consisting  of  carbon  and  oxygen 
weigh  3.78  g.,  what  is  the  formula  of  the  gas  ? 

252.  Compare  the  diffusibilities  of  these  gases,  carry- 
ing the  answer  to  one  decimal  place  :   (a)  N2O  and  CO  ; 
(5)  Br  and  Cl;    <»  N  and  NH3;    (d)  NO   and   H; 
<Y)  CO  and  CO2  ;   (/)  CH4  and  HC1;   (#)  C2H6O  and 
(C2H5)2O;   (A)  H2S  and  CS2;   (i)  H  and  H2S. 

253.  A  gas,  A,  diffuses  3.5  times  faster  than  B\  if 
the  molecular  weight  of  A  is  4,  what  is  that  of  B  ? 

254.  Two  gases,  A  and  J5,  diffuse  approximately  at 
6.1:4.1;    if   A   has   a   molecular  weight   of   34,  what 
should  be  that  of  B  ? 

255.  If  3  1.  of  nitrous  oxide  weigh  5.94  g.,  what  is 
its  vapor  density  ? 

256.  What  is  the  weight  of  1239  1.   of  phosphorus 
vapor  at  +21°  C.  ? 

257.  A  manufacturer  prepares  phosphorus  from  169 
tons  of  bones,  containing  55  %  of  calcium  phosphate ; 
how  much  phosphorus  should  he  obtain  and  how  much 
oil  of  vitriol  ought  he  to  use  ? 

258.  How  much  chlorine  by  volume  can  be  got  from 
10  g.  of  NaCl? 


SYSTEMATIC  REVIEW  187 

259.  If  5  1.  of  turpentine  vapor  are  burned  in  air, 
(«)  what  are  the  products  ;   (b)  what  is  the  volume  of 
the  compound  of  carbon  formed  at  0°  C.  and  760  mm.  ? 

260.  Excess  of  carbon  is  thrown  into  100  g.  of  fused 
niter;    what   volume    of   N   and   of   CO2   is   evolved? 

4  KNO3  +  5  C  =  2  K2CO3  +  4  N  +  3  CO2 

261.  If  the  density  of  marsh  gas  is  0.55  and  its  per- 
centage  composition    is    carbon,  74.95,  and  hydrogen, 
25.05,  prove  that  the  atomic  weight  of  carbon  is  not 
more  than  12. 

262.  Prove  that  the  molecule  of  oxygen  has  at  least 

2  atoms. 

263.  How  many  cc.  of  liquid  water  are  contained  in 
a  rectangular  piece  of  gypsum  (sp.  gr.  =  2.3)  which  is 

3  cm.  x  5  cm.  x  7  cm.  ?     How  much   SO2  is  contained 
in  it? 

264.  When  7  cc.  of  sulphur  vapor  and  5  cc.  of  oxygen 
combine,  so  far  as  possible,  to  form    SO2,  how   many 
cc.  of  SO2  are  formed  and  how  much  of  either  factor  is 
left? 

265.  A  cube  of  crystallized  NaCO3x  10  H2O  (sp.  gr.  = 
1.45)    is    6    cm.   on  a  side,     (#)    What  volume,  as   a 
liquid,   would    the    water    of    crystallization   occupy  ? 
(£)  What  volume  would  the  gaseous    CO2   obtainable 
from  the  salt  at  N.T.P.  occupy  ? 

266.  (a)  How  much  sulphur  by  weight  is  required 
to   make  1000    g.   of   H2SO4?     (5)  If   the   sp.  gr.  of 
H2SO4  is  1.84,  how  many  1.  would  the  acid  occupy  ? 

267.  How  much  SO2  by  volume  could  be  obtained  by 
acting  with  H2SO4  on  a  plate  of  copper  (sp.  gr.  =  8.85) 
which  is  5  cm.  x  8  cm.  x  10  cm.  ? 


188      PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

268.  A  certain  volume  of  gas  at  740  mm.  and  -J-  30°  C. 
weighs  5  g. ;  what  would  an  equal  volume  of  the  same 
gas  weigh  at  760  mm.  and  0°  C.  ? 

269.  Of  two  gases,  A  and  B,  A  diffuses  twice  as  rap- 
idly as  B ;  compare  their  molecular  weights. 

270.  Uranium    is    the    metal    having    the    greatest 
atomic  weight,  238.5;   compute  its  specific  heat  from 
the  atomic  heat. 

271.  GASEOUS  COMPOUNDS  ANALYSES  SP.  GR. 

HX  H:X=1:3  0.557 

OX  O:X  =  8:3  1.529 

HNX  H:N:X  =  2:28:24         0.948 

In  the  above  table  we  have  gaseous  compounds  of  an 
element  X.  The  analyses  of  the  compounds  are  given, 
also  the  sp.  gr.,  air  being  unity.  Air  is  14.4  as  heavy 
as  hydrogen.  What  is  the  atomic  weight  of  the  ele- 
ment X  ?  Give  reasons. 

272.  How  many  1.  of  HC1  at  +  273°  C.  and  760  mm. 
could  be  obtained  by  treating  with  H2SO4  a  cube  of 
rock  salt  (sp.  gr.  =  2.13)  which  measures  5.5  cm.  on 
a  side  ? 

273.  How  many  1.  of  hydrogen  would  be  needed  to 
combine  with  all  the  oxygen  in  50  g.  of  mercuric  oxide  ? 

274.  If  4  1.  of  hydrogen  diffuse  through  an  apparatus 
in  10  minutes,  and  1  1.  of  oxygen  in  an  equal  time  under 
similar  conditions,  what  is  the  density  of  oxygen? 

275.  (a)  How  many  cc.  of  oxygen  at   +33°  C.  are 
needed  to  burn  175  cc.  of  benzene  vapor?     (5)  What 
would  be  formed?     (<?)  What  weight  of  CO2  ? 

276.  I  wish  to  make  30  g.   of  potassium  chloride; 
how  much  potassium  chlorate  ought  I  to  take  ? 


SYSTEMATIC  REVIEW  189 

277.  Assume  that  in  burning  all  2240  Ib.  of  a  certain 
soft  coal  in  gas  retorts,  6  Ib.  of  ammonia  gas  are  liber- 
ated and  collected  in  the  ammoriiacal  liquor ;  that  5  %  is 
lost  in  the  transportation  and  working  of  the  liquor ; 
that  it  is  made  into  ammonium  sulphate.     How  much 
dry  sulphate  of  ammonium  will  it  yield,  and  how  much 
pure   sulphuric   acid  will   be   used   in    the    operation, 
assuming  no  waste  of  acid  ? 

278.  What  volume  at  +  20°  C.  and  under  a  pressure 
of  2  atmospheres  will  100  1.  of  sulphur  dioxide,  meas- 
ured at  0°C.  and  under  a  pressure  of   1    atmosphere, 
occupy  ?     What  weight  of  sulphur  is  necessary  to  pro- 
duce this  amount  of  sulphur  dioxide  ? 

279.  If  the  combustion  of  1  g.  of  sulphur  to  sulphur 
dioxide  develops  2220  calories,  what  is  the  heat  of  com- 
bustion of  sulphur  ? 

280.  Calculate  the  number  of  m.3  of  air  at  +  20°  C. 
needed  for  one  Kg.  of  coal,  the  composition  of  which  is : 
carbon,  76.81%;  hydrogen,  5.14%;    oxygen,   7.90%; 
nitrogen,  1.62  %  ;  sulphur,  1.13  %  ;  water,  1.70  %  ;  ash, 
6.65  %.     Assume  the  factor  for  excess  as  3. 

281.  If  1  volume  of    water  at  -f  20°  C.  absorb  650 
volumes  of   NH3,    what   weight   of   ammonia   will   be 
taken  up  by  1  1.  of  water  at  the  same  temperature  ? 

282.  What  weight  of  NaOH  will  neutralize  100  1.  of 
HC1? 

283.  At  0°  C.   1   volume    of   water  will  absorb  500 
times  its  own  volume  of  HC1.     How  much  will  500  g. 
of  water  at  0°  increase  in  weight  by  absorbing  all  the 
HClitcan? 

284.  What  weight  of  HC1  can  be  obtained  from  25  g. 
of  salt  ?     How  much  Na2SO4  is  formed  ? 


190     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

285.  A  silver  coin  containing  8  %  of  copper  weighs 
2.43  g.     If  the  coin  is  dissolved  in  HNO3,  how  many 
g.  of  NaCl  will  be  needed  to  precipitate  all  the  silver 
as  AgCl  ? 

In  the  above,  what  weight  of  iron  will  be  required  to 
reduce  the  AgCl  to  metallic  silver  and  what  will  be 
the  weight  of  the  silver  obtained  ? 

286.  How  many  tons  of   pure   hematite   would   be 
needed  for  the  production  of  100  tons  of  iron  in  the 
blast  furnace,  assuming  that  2.3%  of  the  iron  in  the 
ore  passes  into  slag  ? 

287.  How  much  coke  would  be  needed  to  reduce  50 
tons  of  pure  hematite  ? 

288.  An   ore    contains    36.4  %    of   "  Ruby    Copper " 
(Cu2O).     With  what  weight  of  charcoal  must  10  tons 
be  heated  to  reduce  all  the  Cu2O  to  metallic  copper  ? 

(Cu2O  +  C  =  2  Cu  +  CO.)  '  Find  weight  of  copper. 

289.  How  much  potassium  hydroxide  will  react  with 
20  g.  of  chlorine,  in  the  formation  of  potassium  chlorate  ? 

290.  How  much  potassium  hydroxide  must  be  used 
to  obtain  5.0  g.  of  potassium  chlorate  ? 

291.  How   much   sodium  hydroxide   will  neutralize 
10  g.  of  nitric  acid  ? 

292.  How  much  sulphuric  acid  will  be  neutralized  by 
20  g.  of  potassium  hydroxide  ? 

293.  How  much  hydrochloric  acid  will  neutralize  25 
g.  of  sodium  hydroxide  ? 

294.  If  40  cc.  of  a  solution  of  potassium  hydroxide 
are  neutralized  by  25  cc.  of  a  solution  of  hydrochloric 
acid  containing  0.001  g.  of  the  acid  per  cc.,  what  weight 
of  the  hydroxide  is  contained  in  10  cc.  of  its  solution  ? 


SYSTEMATIC   REVIEW  191 

295.  If  50  cc.  of  a  solution  of  nitric  acid  are  neutral- 
ized by  70  cc.  of  a  solution  of  sodium  hydroxide  con- 
taining 0.004  g.  of  the  alkali  per  cc.,  what  weight  of 
the  acid  is  contained  in  |  1.  of  its  solution  ? 

296.  If  25  cc.  of  a  solution  of  potassium  hydroxide 
are   neutralized   by  45  cc.  of   a  solution  of   sulphuric 
acid  containing    0.002   g.    of   the    acid   per   cc.,  what 
weight  of  the  hydroxide  is  contained  in  one  1.  of  its 
solution  ? 

297.  How  much  ammonia  gas  can  be  obtained -from 
40  g.  of  ammonium  chloride  ? 

298.  How  much  ammonia  is  necessary  for  the  produc- 
tion of  20  g.  of  ammonium  nitrate  ? 

299.  What  weight  of  nitrogen  will  appear  when  100 
g.   of  chlorine  are  taken  up  in  the  decomposition  of 
ammonia  ? 

300.  How  much  nitrous  anhydride  is  obtainable  from 
60  g.  of  potassium  nitrite  ? 

301.  Calculate    the  weight  of   a  1.    of   nitric  oxide 
under  standard  conditions. 

302.  What  is  the  weight  of  a  1.  of  hydrocyanide  under 
standard  conditions  ? 

303.  A  1.  of  gas  under  700  mm.  pressure  at  +  40°  C. 
weighs  1.307  g.  ;  what  is  its  molecular  weight? 

304.  Five  1.  of  a  gas  under  2  atmospheres  pressure  at 
4-  50°  C.  weigh  10.6  g.  ;  what  is  the  molecular  weight 
of  the  gas  ? 

305.  Seven  1.  of  sulphur  dioxide,  at   +  90°  C.,  are 
produced  by  burning  12  g.  of  sulphur  in  oxygen ;  what 
is  the  pressure  of  the  gas  ? 


192     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

306.  The  oxygen  obtained  from  100  g.  of  potassium 
chlorate  occupies  30  1.  under  the  pressure  of  70  cm.  of 
mercury  ;   what  is  the  temperature  of  the  gas  ? 

307.  What  volume  of  carbon  dioxide  at  +  20°  C.  and 
740  mm.  pressure  would  be  produced  by  the  explosion 
of  10  g.   of  gunpowder  (supposing  gunpowder  to  be 
2  KNO3  +  3  C  +  S)  according  to  the  equation 

2  KN03  +  3  C  +  S  =  3  C02  +  N2  +  K2S  ? 

308.  What  volume  of  nitrous  oxide,  at  -f-  30°  C.  and 
800  mm.  pressure,  is  obtainable  from  100  g.  of  ammo- 
nium nitrate  ? 

309.  How  many  1.  of  hydrogen  will  result  from  the 
electrolysis  of  50  g.  of  water,  when  the  gas  is  collected 
over  mercury,  the  level  within  the  tube  being  90  mm. 
above  that  without,  and  the  temperature  and  barometric 
pressure  being  +  23°  C.  and  745  mm.  respectively  ? 

310.  How  many  g.  of  water  may  be  obtained  by  burn- 
ing a  quantity  of  hydrogen  occupying  400  1.  at  4-  50°  C. 
and  600  mm.  pressure  ? 

311.  Ten  1.  of  a  compound  weigh  19.8  g.     If  T8T  of  it 
is  oxygen  and  the  remainder  carbon,  find  its  formula. 

312.  What  will  be  the  volume  of  a  gas  at  760  mm. 
pressure  and  +  60°  C.,  which  is  2  1.   at  380  mm.   and 
+  90°  C.  ? 

313.  If  70  cc.  of  nitrous  oxide  should  break  up,  what 
would  be  the  weight  of  each  constituent  ? 

314.  A  mixture  of  lead  sulphate  and  barium  sulphate 
weighed  4  g.  and  analysis  of  the  mixture  gave  1.62  g. 
of  SO4 ;  what  are  the  weights  of  lead  sulphate  and  barium 
sulphate  present  in  the  mixture  ? 


SYSTEMATIC  REVIEW  193 

315.  A  mixture  of  the  acid  sulphates  of  sodium  and 
potassium  weighs  0.5  g.,  and  analysis  of  the  mixture 
shows  0.395  g.  of  SO4;  what  weights  of  sodium  and  of 
potassium  are  contained  in  the  mixture  ? 

316.  A  mixture  of  acid  and  neutral  potassium  car- 
bonates weighs  1  g.,  and  contains  0.4  g.  of  carbon  diox- 
ide ;  what  is  the  weight  of  each  carbonate  ? 

317.  A  sample   of  pure  dolomite  weighs  1  g.  and 
yields  0.48  g.  of  carbon  dioxide ;  what  weights  of  cal- 
cium oxide  and  of  magnesium  oxide  does  it  contain  ? 

318.  Which  is  the  more  economical  oxidizing  agent, 
potassium  nitrate  at  5  cts.  a  Ib.  or  sodium  nitrate  at 
5|  cts.  a  Ib.  ? 

319.  Which  is  more  economical  for  neutralizing  an 
alkali,  60  %  nitric  acid  at  6  cts.  a  Ib.  or  30  %  HC1  at 
3  cts.  a  Ib.  ? 

320.  Which  is  the  most  economical  for  making  car- 
bon dioxide,  sodium  dicarbonate  at  3  cts.  a  Ib.,  sodium 
carbonate  crystallized  at  2J  cts.  a  Ib.,  or  calcium  car- 
bonate (marble)  at  1  ct.  a  Ib.  ? 

321.  Which  is  the  more  economical  for  the  prepara- 
tion of  anhydrous  ammonia,  ammonium  sulphate  at  8 
cts.  a  Ib.  or  ammonium  chloride  at  11  cts.  a  Ib.  ? 

322.  Which  is  the  more  economical  oxidizing  agent, 
potassium  chlorate  at  8  cts.  a  Ib.   or  sodium  chlorate 
at  10  cts.  a  Ib.  ? 

323.  Given  two  iron  ores,  one  a  lake  ore  containing 
62  °/0  of  iron  and  the  other  an  ore  containing  45  %  of 
iron,  how  much  of  each  must  be  used  to  give  100  tons 
of  mixture  containing  53  %  of  iron  ? 


194     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

324.  Suppose  we  wish  to  form  100  tons  of  a  mixture 
of  ores  containing  10  %  of  copper,  and  we  have  at  our 
disposal   lots  containing    7  %   and    18  %    respectively ; 
how  many  tons  of  each  must  be  taken  ? 

325.  Given  two  iron  ores,  one  containing  0.52%  of 
phosphorus  and  the  other  0.14%,  how  much  of  each 
must  be  mixed  to  give  20  tons  (2240  Ib.  to  the  ton) 
containing  0.22%  of  phosphorus? 

326.  Given  lead  ores  containing  60  %  and  25  %  of 
lead   respectively,   how   many   Ibs.    of    each   must   be 
mixed  to  give  5000  Ib.  containing  45  %  of  lead  ? 

327.  Suppose    we   have  10  tons  of   coal    containing 
2.5%  of  sulphur.     We  have  also  supplies  of  coal  con- 
taining 0.80%  and  1.10%  of  sulphur.     How  much  of 
each  shall  we  add  to  the  10  tons  to  make  20  tons  con- 
taining 1.80  %  of  sulphur  ? 

328.  Coal  contains  about  2  %  of  nitrogen.    Assuming 
that  75  %  of  this  amount  escapes  as  ammonia  on  distilla- 
tion, calculate  the  amount  of  coal  required  to  furnish 
the  sal-ammoniac  needed  to  produce  10  Kg.  of  NH4OH. 

329.  If  100  volumes  of  Manchester  cannel  gas  con- 
tained 4.98  volumes  of  olefines  which  yielded  on  com- 
bustion 13.93  volumes  of  carbon    dioxide,  what  were 
the  volumes  of  C2H4  and  C4H8  contained  in  the  gas  ? 

330.  One   ft.3  of   hydriodic   acid  is  decomposed  by 
an  excess  of  bromine ;  how  many  ft.3  of  hydrobromic 
acid  are  formed  ? 

331.  If  5  1.  of  chlorine  are  mixed  with  5  1.  of  carbon 
monoxide,  what  volume  of  phosgene  gas  is  produced, 
and  how  much  hydrochloric  acid  and   carbon  dioxide 
would  be  produced    by  the  decomposition  of  this  gas 
with  water  ? 


SYSTEMATIC  REVIEW  195 

332.  How  many  g.  of  water  at  0°  C.  would  be  frozen 
by  the  removal  of  the  heat  required  to  evaporate  50  g. 
of  liquid  ammonia  ? 

333.  Find   the    density   of   the  gas  the  formula   of 
which  is  N2O5.     Find  the  weight  of  a  1.  of  phosphine. 

334.  Calculate  the  volume  of  hydrochloric  acid  solu- 
tion (density  1.10  and  20.9%  pure  acid)  that  is   re- 
quired to  make  500  g.  of   barium    chloride    from  the 
carbonate. 

335.  What  volume  of  air  containing  21  %  of  oxygen 
by  volume  is  required  to  burn  248  g.  of  phosphorus  ? 

336.  If  25.82  1.  of  nitric   oxide    diffuse   through  a 
certain  apparatus  in  50  minutes,  what  volume  of  hydro- 
gen will  diffuse  under  the  same  conditions  ? 

337.  How  many  g.  of  sodium  chloride  dissolved  in  a 
1.  of  water  would  be  required   to  elevate  the  boiling 
point  of  the  solution  0.52°  C.  ? 

338.  How  much  white  lead  should  be  obtained  theo- 
retically from  65  Kg.  of  lead  ? 

339.  How  much  air  would   be  necessary  to  change 
6  1.  of  nitrogen  dioxide  into  the  trioxide?     (Consider 
all  measurements  at  0°  C.  and  760  mm.) 

340.  Suppose  we  had  a  bar  of  aluminum  weighing 
1800  g.,  how  many  cc.  of  water  would  it  displace  ? 

341.  How  much  sodium  nitrate  (98%  pure)  would 
have  to  be  present  in  a  fertilizer  that  contained  4  %  of 
nitrogen,  assuming  that  all  the  nitrogen  came  from  the 
nitrate  ? 

342.  How  many  g.  of  KI  dissolved  in  a  1.  of  water 
are  necessary  to  lower  the  freezing  point  of  the  solu- 
tion +  1.86°  C.  ? 


196     PROGRESSIVE  PROBLEMS  IN    CHEMISTRY 

343.  Find  the  density  of  the  gas  having  the  formula 
N2. 

344.  Find  the  weight  of  a  1.  of  hydrogen  chloride. 

345.  One  1.  of  gas  weighs  0.09  g. ;  find  its  molecular 
weight.      What  is  this  gas  ? 

346.  How  much  sodium  would  be  necessary,  assum- 
ing exact  proportions,  to  produce  3  Kg.  of  aluminum 
from  2  A1C13,  2  NaCl  ? 

347.  How  many  cc.  of  a  solution  of  potassium  per- 
manganate which   contains   40  g.  to   the  1.  would   be 
necessary  to  oxidize  0.5  g.  of  iron  from  the  ferrous  to 
the  ferric  condition  ? 

348.  How   much  aluminum  should  we  theoretically 
obtain  from  an  ore  containing  90  %  of  bauxite  ? 

349.  If  500  g.  of  sulphur  containing  17%  impurities 
are  burned  in  air,  what  weight  of  oxygen  is  needed  ? 

350.  If  2  g.  of  gunpowder  produce  600  cc.  of  gas 
at  0°  C.,  what  is  the  volume  at  +  2500°  C.  ? 

351.  What  weight  of  carbon  is  contained  in  (V)  1  1. 
CO  ;  (5)1 1.  CO2;  (<?)  1 1.  C2H2;  (d)  1  1.  CH4;  («)  1 1. 
C2H4? 

352.  The  velocity  of  diffusion  of  nitrogen  is  1.0143; 
how  many  atoms  of  nitrogen  are  there  in  a  molecule  ? 

353.  The  velocity  of  diffusion  of  oxygen  is  0.9487; 
how  many  atoms  of  oxygen  are  there  in  a  molecule  ? 

354.  If   25   cc.  of    dilute    H2SO4   required   2.44   g. 
BaCl2,  2  H2O  for  complete  precipitation,  what  percent- 
age of  water  was  present  in  the  dilute  acid  ? 

355.  How  much  H2SO4  is  needed  to  decompose  27  g. 
of  common  salt  ? 


SYSTEMATIC   REVIEW  197 

356.  What  is  the  weight  of  40  1.  of  NH3  at  0°  C.  and 
760  mm.  ?     If  40  1.  of  HC1  are  mixed  with  it,  what  is 
the  weight  of  the  residue  ? 

357.  If  20  g.  oxalic  acid  are  warmed  with  H2SO4,  how 
much  CaCO3  can  be  produced  by  passing  the  products 
through  lime   water   and  what  volume  of   gas  passes 
over? 

358.  If  130  g.  of  NH3  burn,  what  are  the  weights  of  the 
products  of  combustion  ? 

359.  Calculate  the  effect  of  adding  2  volumes  of  a 
saturated  (3.90  molar)  solution  of  potassium  chloride 
to   a   saturated    (0.52    molar)    solution   of   potassium 
chlorate.     Assume  that  1.95  molar  KC1  is  0.71  ionized. 

360.  The  sum  of  the  readings  of  the  same  temperature 
on  the  F.  and  C.  scale  is  172 ;  what  is  the  reading  on 
each  ? 

361.  A  sample  of  carbon  containing  85  %  of  carbon 
and  3%  of  hydrogen  is  burned;  what   volume  of  air 
containing  21  %  of  oxygen  is  used  ? 

362.  What  weight  and  volume  of  air  contain  1  g. 
of  nitrogen  ? 

363.  What  volume  of  chlorine  acting  on  NH3  will 
give  10  1.  of  nitrogen  ? 

364.  Give  the  sum  and  the  difference  in  weight  of  20 
1.  of  nitrogen  and  20  1.  of  air. 

365.  To  give  6  1.   of  PH3,  how  much  zinc  must  be 
treated  with  sulphuric  acid  to  give  the  required  amount 
of  hydrogen  ? 

366.  If  13  g.  As2S3  have  been  thrown  down  in  a 
solution  by  the  passage  of  H2S,  what  volume  of  H2S 
at  +  16°  C.  and  761  mm.  was  used  ? 


198      PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

367.  How  much  As2O3  corresponds  to  12  g.  of  As2S3  ? 

368.  If  1.311  g.  of  As2S3  were  obtained  as  a  result  of 
the  analysis  of  the  stomach  in  a  poison  case,  how  much 
paris  green  was  swallowed  ? 

369.  To  produce  20  g.   P2O5,  how  much  (a)  phos- 
phorus and  how  much  (b)  PH3  must  be  burned? 

370.  One  g.  of  hydrogen  is  passed  over  100  g.  of 
CuO  ;  find  weight  of  H2O  and  the  loss  of  the  CuO. 

371.  How  many  oz.  of  gold  per  ton  are  represented 
by  40  parts  to  the  million?     What  would  be  the  value 
of  such  ore,  rating  gold  at  $20.00  per  oz.? 

372.  From  the  following  data  calculate  the  weight  in 
Kg.  of  each  constituent  of  the  air  in  a  room  12'  0"  x 
15'   0"  x  9'   0" :  —  Composition  of  the  air  by  volume  : 
nitrogen,    77.35%;    oxygen,  20.77%;    argon,  0.94%; 
water  vapor,  0.90%  ;  carbon  dioxide,  0.03%  ;  a  1.  of  air 
of  above  composition  weighing  1.29  g. 

373.  From  the  following  data  calculate  the  weight  in 
Kg.  of  each  constituent  of  the  air  in  a  room  12'  x  15'  x 
9' :  assume  water  vapor  =  0.90  %  and  carbon  dioxide  = 
0.03%. 

374.  The   sp.  gr.    of   zinc   is   7.2.     A   block   of   it 
2  cm.  x  3  cm.  x  4  cm.  is  dissolved  in  HC1.     How  much 
hydrogen  (a)  by  weight  and  (5)  by  volume  is  evolved? 

375.  A  block  of  charcoal  -^  pure  is  5  cm.  x  6  cm. 
X  7  cm.,  and  has  sp.  gr.  =  1.5  ;  how  much  CO2  by  vol- 
ume ought  to  form  in  burning  it? 

376.  If  PbCO3  has  a  sp.  gr.  =  6.46,  how  much  CO2 
by  volume  could  be  obtained  from  a  cubical  mass  of  it, 
7  cm.  on  a  side? 


SYSTEMATIC  REVIEW  199 

377.  At  60  cents  per  oz.,  what  is  the  value  of  the 
silver  in  ^  Ib.  of  silver  nitrate  ? 

378.  If    a    skeleton    weighs    21    Ib.    and    is    56  % 
Ca3(PO4)2,  how  many  matches  can  be  tipped  with  the 
phosphorus  it  contains,  if  1  Ib.  of  phosphorus  serves  to 
tip  a  million  matches  ? 

379.  How  much  iron  is  present  in  a  solution  which 

M 

requires  47  cc.  of  a  —  solution  of  KMnO4  to  produce  a 

pink  color? 

380.  If  5.24  g.  coke   on  burning  give  17.54  g.  of 
CO2,  what  is  the  percentage  of  carbon  in  the  coke? 

381.  If  2  g.  were  lost  by  heating  a  piece  of  Iceland 
spar,  what  weight  and  volume  of  CO2  were  produced  at 
+  13°C.  and  700mm.? 

382.  How  much  HF  by  volume  is  needed  to  reduce 
the  weight  of  a  piece  of  glass  3  g.? 

383.  If  300  tons  carbon  (87  %  pure)  are  burned  in 
air,  how  much  oxygen  is  needed  ?     What  volume  of  gas 
is  produced  at  -  6°  C.  and  721  mm.? 

384.  What  volume  of  gas  is  given  by  1  g.  of  "black 
lead"  on  complete  combustion  at  standard  conditions? 

385.  If  12.1764  1.  of  nitrogen  diffuse  through  a  po- 
rous plate  in  the  time  that  it  takes  9.7044  1.  of  CO2  to 
do  so,  what  is  the  density  of  CO2  compared  with  air? 

386.  If  300  1.  of  nitrogen  dioxide  diffuse  through  a 
porous  plate  in  1  hour,  what  volume  of  silicon  tetra- 
fluoride  will  diffuse  through  in  the  same  time  ? 

387.  The  sp.  gr.  of  bromine  is  3.18 ;  find  the  volume 
of  vapor  given  off  when  measured  at  +  90°  C. 


200     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

388.  How  much  H2SO4  will  20  g.  of  SO3  dissolved  in 
water  yield? 

389.  If  60  1.  of  nitrogen  tetroxide  diffuse  through  a 
porous,  plate  in  1  hour,  what  volume  of  chlorine  tet- 
roxide will  diffuse  through  in  the  same  time  ? 

390.  How  many  g.  of  MnO2  and  how  many  cc.  of  a 
solution  of  HC1  (containing  20  %  of  HC1)  are  necessary 
to  evolve  1.86  1.  of  chlorine  at  0°  C.  and  760  mm.  ? 

391.  How  much  water  will  be  formed  by  the  action 
of  (a)  copper  upon  98  g.   of  hot  hydrogen  sulphate  ; 
(5)  hydrogen  fluoride  upon  60  g.  of  silicon  dioxide  ? 

392.  If  120  cc.  of  a  mixture  of  CO  and  hydrogen  are 
exploded  with  oxygjen,  40  cc.  of  gas  remain,  of  which 
30  cc.  are  absorbed  by  KOH  solution ;  find  the  compo- 
sition of  the  mixture. 

393.  If  20  1.  of  hydrogen  diffuse  through  a  porous 
plate  in  10  minutes,  determine  the  volume  of  nitrogen 
monoxide  that  will  diffuse  through  in  the  same  time. 

394.  If  x  cc.  of  a  gas  are  measured  at  +  15°  C.  and 
755  mm.,  the  normal   volume  is  1:000   cc. ;    find   the 
numerical  value  of  x. 

395.  The  sp.  gr.  of  ammonia  gas  under  standard  con- 
ditions is  0.591 ;  what  is  its  sp.  gr.  when  the  barometer 
stands  at  750  mm.  ? 

396.  The  sp.  gr.  of  chlorine  is  2.45  under  standard 
conditions ;    what   is  the  barometric  height  when  the 
sp.  gr.  is  2.40  ? 

397.  One  1.  of  hydrogen  under  standard  conditions 
weighs  0.0896  g. ;  what  is  the  weight  of  1  1.   when 
the  barometer  stands  at  740  mm.  ? 


SYSTEMATIC   REVIEW  201 

398.  One  1.  of  air  under  standard  conditions  weighs 
1.29  g. ;  what  is  the  weight  of  2.5  1.  when  the  barome- 
ter stands  at  755  mm.  ? 

399.  If  72  g.  of  an  aqueous  solution  of  H2O2,  when 
decomposed,  give  2.79  1.  of  oxygen  at  0°  C.  and  760 
mm.,  what  is  the  percentage  of  H2O2  in  the  solution? 

400.  Sea  water  contains  0.00475   g.   CaCO3  per  1.  ; 
what  quantity  of  sea  water  would  be  needed  to  prepare 
56  g.  of  lime  ? 

401.  If  21  g.  of  borax  are  heated  to  constant  weight, 
what  is  the  loss  and  what  per  cent,  of  the  whole  ? 

402.  Silicon  fluoride  was  passed  into  cold  water  and 
27  g.   of  SiO2  were  produced ;  how  much  of  the  gas 
was  used  ? 

403.  A  gas  is  composed  of  92.3  %  of  C  and  7.7  %  H  ; 
how  many  atoms  of  hydrogen  are  united  to  2  atoms 
of  carbon  ? 

404.  If  hydrogen  sulphide  is  diluted  with  10  times 
its  volume  of  hydrogen,  what  volume  of  it,  estimated  as 
pure  gas,  will  be  dissolved  by  20  volumes  of  alcohol  at 
0°  C.  and  760  mm.  ? 

405.  A  Dumas  bulb  full  of  air  weighs  13.3125  g. 
After  being  filled  with  the  vapor  of  carbon  tetrachloride 
at  100°  C.,  it  weighs  13.7969  g.     Filled  with  water,  it 
weighs  141.3  g.     The  barometric  reading  is  755  mm. 
What  is  the  vapor  density  referred  to  air  at  0°  C.  and 
760  mm.  ? 

406.  What  volume  of  air  is  required  to  oxidize  one 
formula-weight  of  zinc  sulphide  to  ZnO  and  SO2,  and 
what  volume  of  sulphur  dioxide  is  produced  ?     Is  the 


202      PROGRESSIVE   PROBLEMS  IN   CHEMISTRY 

product  more  or  less  diluted  with  nitrogen  than  when 
pure  sulphur  is  burned,  and  by  how  much  ? 

407.  How  much  chlorine  is  needed  to  displace  bromine 
in  a  solution  of  NaBr  containing  16  g.  ? 

408.  How  many  g.  of  sulphur  in  3  1.  of  SO2;   6  g. 
of  S08;  10  1.  of  H2S;  16  g.  of  K2SO4? 

409.  If   8.132   1.   of   CO    diffuse  through   an   open- 
ing in  the  time  that  .it  takes  10.7  1.  of  marsh  gas  to 
pass  through,  what  is  the  density  of  marsh  gas  compared 
with  that  of  air  ? 

410.  If  3.804  1.  of  oxygen  diffuse  through  a  certain 
opening  in  the  time  that  it  takes  4.066  1.  of  CO  to  pass 
through,  what  is  the  density  of  CO  compared  with  that 
of  air  ? 

411.  Determine  the  density  of  oxygen  compared  with 
air,  given  that  5.706  1.  of  oxygen  diffuse  through  a  hole 
in  the  time  it  takes  22.68  1.  of  hydrogen  to  pass  through. 

412.  What  volume  of  HI  weighs  the  same  as  J  1.  of 
oxygen  at  0°  C.  and  760  mm.  ? 

413.  A    solution    of   common  salt  required  6  g.  of 
AgNO3  to  precipitate  it  completely  as  AgCl ;  how  much 
sodium  was  present  ? 

414.  If  150  tons  of  H2SO4  are  made  from  110  tons  of 
a  crude  native  sulphur,  find  the  percentage  of  sulphur 
in  the  native  product. 

415.  One  ton  of  iron  pyrites  containing  50  %  sulphur 
will  make  how  much  H2SO4  ? 

416.  A  fire  extinguisher  contains  2  Ib.  of  NaHCO3; 
how  much  H2SO4  is  needed  to  neutralize  it  ? 


SYSTEMATIC  REVIEW  203 

417.  One  g.  of  coal  gave  0.2000  g.  of  barium  sulphate; 
1  g.  of  magnesium  oxide  and  0.50  g.  of  sodium  carbonate 
were  used  in  the  analysis.     It  was  found  upon  a  blank 
analysis  of  the  reagents  that  10  g.  of  the  magnesia  and 
5  g.  of  sodium  carbonate  together  gave  0.1500  g.  of 
BaSO4.     What  is  the  percentage  of  sulphur  in  the  coal  ? 

418.  In  the  analysis  of  a  limestone,  1  g.  was  taken 
for  analysis,  and  a  precipitate  of  CaSO4  weighing  0. 812  g. 
was  obtained.     A  precipitate  of  magnesium  pyrophos- 
phate  weighing  0.385  g.  was  also  obtained.     What  is 
the  percentage    composition  of  the   limestone  in  CaO 
and  MgO  ? 

419.  Find  the  weight  and  volume  of  oxygen  needed 
for  the  complete  combustion  of  10  g.  of  C2H4. 

420.  How  much  CO2  in  a  room  10  m.  x  6  m.  x  4  m., 
if  there  is  1  volume  CO2  in  10,000  volumes  of  air? 

421.  How  many  1.  of  CO2  must  be  passed  over  hot 
charcoal  to  give  100  g.  of  CO  ? 

422.  Sixty  1.  of  steam  require  what  volume  of  the 
component  gases  ? 

423.  What  volume  of  chlorine  would  be  equal  to  24  1. 
of  methane  at  0°  C.  and  760  mm.  ? 

424.  If  200  cc.  of  oxygen  are  exploded  with  40  cc- 
of   marsh   gas,  what   are  the  volumes  and  percentage 
compositions  of  the  residual  gases  ? 

425.  If  3.36  g.    of   three   different   metals   liberate 
respectively  1344  cc.,  3136  cc.,  and  1636  cc.  of  hydro- 
gen, what  metal  was  dissolved  in  each  case  ? 

426.  What  weight  of  alcohol  and    what   volume  of 
CO2  on  fermentation  are  produced  by  21  g.  of  grape 
sugar  ? 


204      PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

427.  Gunpowder  is  composed  of  75  parts  niter,  15 
parts  charcoal  and  10  parts  sulphur.     If  all  the  carbon 
forms    CO2   and    the   nitrogen   is   liberated,    find    the 
volume  of  these  gases  evolved  on  the  explosion  of  1  g. 
of  gunpowder  at  standard  conditions. 

428.  At  the  ordinary  temperature  and  pressure,  water 
absorbs  50  %  of  its  weight  of  ammonia.     Calculate  the 
amount  of  sal-ammoniac  and  quicklime  needed  to  pro- 
duce 10  Kg.  of  hartshorn. 

429.  According  to  Boussingault,  a  m.2  of  leaf  will 
decompose    in    sunlight    1.108    1.    of    carbon    dioxide 
in  an   hour.     Calculate   in   tons   the   amount   of   car- 
bon  assimilated    in   an  hour  by  1,000,000  trees,  each 
possessing   100,000    leaves   and    each    leaf    containing 
25    cm.2      Calculate    the    volume    of    the    carbon    so 
assimilated,  on  the  assumption  that  it  possesses  a  sp. 
gr.  of  2.6. 

430.  If  sea  water  contains  0.36  parts  MgBr2  in  1000, 
how  much  of  it  would  be  needed  to  give  1  1.  of  bro- 
mine (sp.  gr.  =  3.18)? 

431.  lodic  acid  may  be  obtained  by  passing  a  stream 
of  chlorine  through  water  containing  iodine  in  suspen- 
sion ;  how  much  iodine  and  chlorine  will  be  needed  to 
prepare  100  g.  of  iodic  acid  ? 

432.  What  weight  of  iron  sulphide  will  be  needed  to 
yield  a  1.  of  hydrogen  sulphide  at  0°  C.  and  760  mm., 
and  how  much  air  will  be  required  to  burn  this  gas  com- 
pletely to  water  and  sulphur  dioxide  ? 

433.  Manchester  coal  gas  contains  35  %  by  volume  of 
marsh  gas ;  calculate  the  weight  of  this  gas  in  a  gas- 
ometer holding  100,000  ft.3  of  coal  gas. 


SYSTEMATIC  REVIEW  205 

434.  If  100  g.  of  pure  silver  cyanide  are  shaken  up 
with  120  g.  of  hydrochloric  acid  containing  26.1%  of 
HC1,  how  much  silver  chloride  is  produced  and  what  is 
the  percentage  amount  of  hydrocyanic  acid  in  solution? 

435.  A  water  solution  of  potassium  iodide   having 
20  g.  in  it  is  treated  with  chlorine ;  what  volume  of 
chlorine  will  be  needed  to  replace  all  the  iodine  ? 

436.  Sulphuric  ether  vapor  is  exploded  with  60  times 
its  volume  of  air ;  find  volumes  of  residual  gases. 

437.  If  300  cc.  of  oxygen  were  added  to  200  cc.  of  a 
mixture  of  H,  CO  and  CH4,  and  if,  after  exploding,  the 
volume  was  220  cc.,  and  after  washing  with  KOH  so- 
lution 80  cc.,  what  was  the  composition  of  the  mixture? 

438.  Five  volumes  of  a  hydrocarbon,  CnH2ra,  are  sub- 
mitted to  combustion  ;   how  many  volumes  of  oxygen 
are  required  for  its  complete  combustion  and  how  many 
volumes  of  CO2  are  generated  ? 

43d.    Find  weight  of   hydrogen   necessary   to   unite 
with  oxygen  in  200  g.  of  air  to  form  water. 

440.  Find  volume  of  oxygen  needed  to  unite  with 
2  1.  of  hydrogen  to  form  water.     What  volume  with 
(a)    60    cc.  ;    (5)    60   dm.3;    (c)    60  1.  ;    (d)  60  qt. ; 
0)  60  M.3;   (/)  700  volumes? 

441.  Find  the  weight  of  (a)  700  cc.  of  dry  hydrogen 
at  0°  C.  and  760  mm.  ;   (5)  of  2000  cc.  ;   (c)  of  13  1.; 
(d)  16J  dm.3;   (e)  3  m.3 

442.  One  Kg.  of  water  contains  hydrogen  and  oxygen 
in  what  proportion  by  weight  and  by  volume  ? 

443.  Find  the  weight  of  1200  1.  of  phosphorus  vapor. 

444.  Arsenic  is  burned  in  oxygen  and  103  g.  of  the 
oxide  are  produced ;  how  much  arsenic  was  used  ? 


206     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

445.  A  tank  holds  20  g.  of  oxygen  ;  what  weight  (a) 
of  N2O  and  of  (6)  NO  will  it  hold  ? 

446.  If  potassium  is  heated  in  contact  with  10  g.  of 
N2O  and  NO  separately,  what  volume  of  nitrogen  will 
be  left  in  each  case? 

447.  How  much  pure  HNO3  in  200  tons  of  HNO3, 
200  g.  of  which  will  neutralize  88.6  g.  of  pure  NaOH  ? 

448.  What  loss  in  weight  should  100  Ib.  of  gypsum 
undergo  when  heated  to  +  250°  C.? 

449.  If  0.4  g.  of  iron  dissolved  in  acid  gave  167.4  cc. 
of  hydrogen  at  -f  12°  C.  and  750  mm.,  what  is  the  purity 
of  the  iron? 

450.  How  much  coke  (90  %  pure  carbon)  would  be 
needed  to  make  100  m.3  of  CO,  measured  at  +  30°  C. 
and  850  mm.? 

451.  If  0.2  g.  of  a  metal  yield  77.39  cc.  of  hydrogen, 
how  much  will  yield  309  cc.? 

452.  If  600  cc.  oxygen  at  +  12°  C.  and  720  mm.  are 
required,  and  the  materials  on  hand  are  bleaching  pow- 
der, cobalt  oxide  and  water,  how  much  bleaching  pow- 
der will  be  used? 

453.  What  volume  of  HI  contains  2  g.  of  iodine  at 
standard  conditions? 

454.  If  1  cc.  HC1  neutralizes  0.0106  g.  Na2CO3,  what 
weight  of  AgCl  will  be  thrown  down  when  1  cc.  is 
added  to  excess  of  AgNO3  solution? 

455.  A  mixed  gas  consists  of  hydrogen  46%,  CH4 
40%,  and  olefiant  gas  14%  by  volume  ;  how  much  air 
would  be  needed  to  burn  100  1.  of  this  gas? 

456.  Find  the  weight  of  20  1.  of  air  containing  21  % 
of  oxygen  and  79  %  of  nitrogen  at  0°  C.  and  760  mm. 


SYSTEMATIC   REVIEW  207 

457.  In  300  g.  of  common  alum,  find  how  much  alu- 
minum is  present. 

458.  A  slab  of  marble  weighs  200  Kg.     (a)    How 
much  lime  will  it  make  ?     (6)  What  volume  of  water 
will  just  slake  this  lime?     (c)  How  many  1.  of  air  will 
transform  it  into  the  carbonate  ?     (1  volume  of  CO2  in 
10,000  volumes  of  air.) 

459.  When  50  g.  of  ZnO  were  made,  how  much  zinc 
was  needed  and  what  volume  of  oxygen  was  used? 

460.  What  weight  of  HC1  would  be  needed  to  dis- 
solve 200  g.  of  ZnO? 

461.  If  20  cc.  of  H2SO4  solution  yield  2.468  g.  of 
BaSO4  when  precipitated  with  BaCl2,  what  weight  of 
this  acid  will  be  required  to  neutralize  10  g.  of  Na2CO3? 

462.  What  volume  of  sulphuric  ether  vapor  corre- 
sponds in  weight  to  (a)  11.  of  nitrogen ;   (J)  1  1.  of 
air;   (V)  1  1.  CO2;   (d)  1  1.  of  chlorine? 

463.  What  weight  of  phosphoric  acid  could  be  made 
from  10  Ib.  of  phosphorus? 

464.  On  heating  sodium  phosphate  till  there  is  no 
longer  a  loss  in  weight,  one  gets  100  g.  of  residue ; 
what  was  the  original  weight? 

465.  An  unknown  volume  of  hydrogen  sulphide  re- 
quired 110.34  cc.  of  chlorine  for  complete  decomposi- 
tion ;  what  was  the  volume  of  the  hydrogen  sulphide  ? 

466.  One  g.  of  NaCl  in  solution  was  mixed  with  an- 
other solution  containing  2  g.  of  AgNO3.     Find  weight 
of  residue.     Which  one  was  in  excess  and  how  much  ? 

467.  How  much  CaC2  will  produce  enough  gas  from 
water  to  yield  on  combustion  20  1.  of  CO2,  measured  at 
+  10°  C.  and  730  mm.  ? 


208     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

468.  If  25  g.  of  sodium  acetate  yield  a  certain  weight 
of  CH4,  what  volume  of  air  (21  %  oxygen)  is  needed 
to  burn  this  gas? 

469.  If  24  g.  of  magnesium  are  heated  in  a  current 
of  nitrogen,  what  is  the  weight  of  the  product? 

470.  I   need   2   1.    of    CO2.     What  weights  of   (a) 
Na2CO3  and  (5)  NaHCO3  would  have  to   be   treated 
with  acid  to  give  this  volume? 

471.  What  is  the  weight  of  100  1.  of  SOa,  measured 
at  +  31°  C.  and  721  mm.  ? 

472.  What  volume  of  CO,  at  +  800°  C.  and  700  mm., 
would  be  required  to  reduce  1  Kg.  of  ferrous  oxide  to 
metallic  iron  ? 

473.  A  1.  of  mineral  water  yielded  0.0134  g.  of  Agl ; 
how  much  iodine  is  contained  in  1,000,000  cc.  of  the 
water  ? 

474.  From  the  vapor  densities  of  these  gases  com- 
pute their  molecular  weights  :   (a)  oxygen,  16  ;   (5)  car- 
bon dioxide,  22 ;  (<?)  nitrogen,  14;  (<f)  nitric  oxide,  15; 
(e)  carbon  monoxide,  14 ;   (/)  marsh  gas,  8. 

475.  Find  the  vapor   densities   of   these   molecules, 
computing  the  molecular  weights  by  affixing  the  atomic 
weights:' (a)  HC1;    (5)   C2H2;   (c?)   NH3 ;    (d)  PH3 ; 
0)  02;   (/)  P4;   (g)  Hg  ;   (A)  CO  ;   (*)  CH4. 

476.  (a)  The  vapor  density  of  alcohol  is  23.     As- 
certain which  of  the  following  is  the  proper  formula 
for  alcohol:   (1)  C4H12O2 ;   (2)  C2H6O ;   (3)  C8H24O4. 
(7>)  The  vapor  density  of  acetic  acid  is  29.7,  and  the 
percentage  composition  indicates  one  of  these  symbols. 
Which   is   correct:      (1)    H2CO ;     (2)    H6C3O3 ;     (3) 
H4C2O2?     (V)  To  which  of  these   formulas  does   the 
density  33.5  apply:   (1)  C1O2;   (2)  C12O4? 


SYSTEMATIC  REVIEW  209 

477.  What  weight  of  calcium  carbonate  is  required 
to  neutralize  400  cc.  of  hydrochloric  acid  solution  which 
contains  100  g.  of  the  pure  substance  ? 

478.  The  specific  heat  of  phosphorus  is  0.189.     The 
vapor  density  of  phosphorus  is  62.     How  many  atoms 
are  there  in  the  molecule  of  phosphorus  gas  ? 

479.  How  much  nitrogen  may  be  obtained  from  22  g. 
of  ammonium  nitrite  ?     What  volume  would  it  occupy 
at  +  20°  C.  and  756  mm.  pressure? 

480.  In  every  100  parts  of  nitric  acid  there  are  1.58 
parts  of  H,  76.19  parts  of  O,  and  22.23  parts  of  N. 
Does  this  fix  the  formula  of   the  acid?     Why  do  we 
accept  the  formula  HNO3? 

481.  If  100  g.  of  gypsum  are  heated,  what  volume 
of  steam  at  +  300°  C.  is  given  off? 

482.  How  much  carbon  dioxide  by  weight  and  by 
volume  can  be  obtained  from  53  g.  of  sodium  carbonate? 
What  volume  would  the  gas  occupy  at   +  20°  C.  and 
under  a  pressure  of  75  mm.  ? 

483.  A  1.  of  a  certain  gas  weighs  7.50  g.,  while  a 
1.  of  hydrogen  under  the  same  conditions  weighs  0.050  g. 
The  atomic  weight  of  the  element  composing  the  gas 
is  75.     How  many  atoms  are  there  in  one  molecule  of 
the  gas? 

484.  What  volume  of  oxygen  under  standard  condi- 
tions can  be  obtained  from  5  g.  of  potassium  chlorate? 

485.  What  is   the   atomic  weight   of   silver,  if   the 
specific  heat  is  0.056  and  the  atomic  heat  is  5.99  ? 

486.  Find  the  specific  heat  of  silver,  if  the  atomic 
weight  is  107  and  the  atomic  heat  is  5.99. 


210     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

487.  Compute    atomic    heats    from    the    data   that 
follow:   (a)  Hg,  at.  wt.  199,  sp.  ht.  0.033;   (ft)  iodine, 
at.  wt.  126,  sp.  ht.  0.054;   (<?)   U,  at.  wt.   238,  sp.  ht. 
0.028  ;   (d)  Br,  at,  wt.  80,  sp.  ht.  0.1071. 

488.  Take  6.4  as  the   atomic  heat  of  the  following 
and  the  specific  heats  as  given,  and  find  the  approxi- 
mate   atomic    weights:     (a)    Al,   0.22;    (ft)  Fe,  0.11; 
(<?)  Zn,  0.094  ;   (d)  K,  0.17  ;   (e)  Pb,  0.031. 

489.  Hydrogen  is  passed  over  hot  copper  oxide,  and 
the  water  that  is  formed  is  absorbed  by  calcium  chloride 
and  its  weight  ascertained  to  be  3  g. ;  what  has  been 
the  loss  of  weight  of  the  tube  containing  the  copper 
oxide  ? 

490.  Two  1.  of  a  gas  which  is  half  oxygen  and  half 
sulphur  weigh  5.76  g.  ;   what  is  its  formula  ? 

491.  A  compound  of  nitrogen  and  hydrogen,  of  which 
the  nitrogen  is  \$,  weighs  0.765  g.  to  the  1.;  what  gas 
is  it? 

492.  Two  1.  of  a  compound  of  oxygen  and  nitrogen 
weigh    3.96   g.       The   nitrogen   is   ^   of    the   whole. 
What  is  the  compound  ? 

493.  Find  the  specific  heat  of  each  of  the  following 
elements  from  the  constant  atomic  heat  6.4 :   (a)  Mg, 
at.  wt.   24 ;  (ft)  Ni,  at.  wt.   58 ;  (c)  Pt,  at.  wt.   193  ; 
(cf)  Na,  at.  wt.  23. 

494.  The  atomic  weight  of  copper  is  either  31.5  or 
63;  find  which  is  correct  if  the  specific  heat  is  0.094. 

495.  If  zinc  has  an  atomic  weight  of  either  32.5  or 
65  or  130,  find  which  is  correct  if  the  specific  heat  of 
Zn  is  0.094. 


SYSTEMATIC   REVIEW  211 

496.  If   1   1.   of   acetylene  is   burned,  what  volume 
of   oxygen  is  necessary  for  the  combustion  and  what 
volume  of  carbon  dioxide  will  be  formed? 

497.  What   weight    of    carbon    dioxide    would    be 
obtained  by  burning  17  g.  of  carbon  ? 

498.  What  volume  of  oxygen  will  unite  with  730  cc. 
of  carbon  monoxide  to  form  carbon  dioxide  and  what 
will  be  the  volume  of  the  carbon  dioxide  produced? 

499.  Supposing   standard   conditions   in   each    case, 
find  the  weight  of  a  1.  of  ammonia,  NH3;   CO2;  CO; 
N2;  H2S;   N2O3 ;   C12. 

500.  By  analysis  we  find  aluminum-methyl  to  con- 
tain 37.5  %  of  Al,  50  %  of  C,  and  12.48  %  of  H.     The 
vapor  density  is  very  nearly  72   at   +  160°  C.,  but  at 
+  220°  C.   it  is  found  to  be  nearly  36.     Can  you  ac- 
count for  the  vapor  density  varying  at  the  two  tem- 
peratures ?     What  is  the  formula  of  the  compound? 

501.  Carbon  and  oxygen  form  what  compounds?     If 
1  1.  of  oxygen  combines  with  carbon  to  form  each  of 
these  compounds,  what  will  be  its  volume  in  each  case, 
at  the  standard  temperature  and  pressure? 

502.  What  is  the  sp.  gr.  referred  to  air  and  to  hydro- 
gen of  a  gas  that  requires  12  minutes  to  escape  through 
an  opening,  while  the  same  volume  of  air  under  same 
conditions    of   temperature   and   pressure  requires    20 
minutes  ? 

503.  If  an  ore  contains  10%  of  moisture  and  12%  of 
copper,  what  will  be  the  percentage  of  copper  in  the  ore 
dried  at  +105°  C.? 

504.  If  an  ore  contains  15  %  of  moisture  and  50%  of 
manganese,  what  will  be  the  percentage  of  manganese 
in  the  dry  ore  ? 


212     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

505.  What  is  the  sp.  gr.  referred  to  air  of  a  gas  that 
escapes  in  14.5  minutes  through  an  opening,  through 
which,  at  the  same  temperature  and  pressure,  the  same 
volume  of  air  requires  19.5  minutes  ? 

506.  What  is  the  vapor  density  of  a  gas  that  escapes 
in  7  minutes  and  30  seconds  from  an  opening,  while  the 
same  volume  of  air  under  the  same  conditions  requires 
5  minutes  and  10  seconds  ? 

507.  If  a  sample  of  coal  contains  10%  of  ash  on  the 
dry  basis,  what  is  the  percentage  of  ash  in  the  natural 
coal  containing  5  %  of  moisture  ? 

508.  A  sample  of  ore  contained  20  %  of  lead,  14  %  of 
zinc  and  14%  of  water;  what  are  the  percentages  of 
lead  and  zinc  on  the  dry  basis  ? 

509.  A  clay  was  partially  dried  and  then  contained 
SiO2,  50  %,  and  water  1  %  ;  the  original  clay  contained 
12  %  of  water ;  what  is  the  percentage  of  the  silica  in 
the  original  sample  ? 

510.  Find  the  proportion  by  weight  and  by  volume 
in  which  ethane  gas  will  combine  with  oxygen. 

511.  A    quantity   of    hydrogen    measures   76   1.    at 
+  100°  C.  and  746  mm.  pressure;    calculate  its  weight. 

512.  The  equivalent  of  mercury  is  100,  and  the  for- 
mula of  mercuric  chloride  is  HgCl2 ;    find  its  specific 
heat. 

513.  The  formula  of  ethane  is  C2H6.     Calculate  the 
density  of  its  vapor  (a)  compared  with  hydrogen;  (6) 
compared  with  air. 

514.  If  an  ore  contains  60%  of  iron  in  the  dry  sample, 
what  is  the  percentage  of  iron  in  the  natural  ore  which 
contains  10  %  of  water  ? 


SYSTEMATIC   REVIEW  213 

515.  What  is  the  amount  of  "  available  oxygen  "  in 
a  cc.  of  a  solution  of  potassium  permanganate  contain- 
ing 50  g.  per  1.  ? 

516.  Find  the  weight  of  10  cc.  of  iron  when  sp.  gr. 

is  7.85. 

517.  If  100  g.  of  a  solution  of  hydrogen  dioxide  in 
water  gave  off,  when  heated,  5  1.  of  oxygen,  what  is 
the  percentage  of  H2O2  in  the  solution  ? 

518.  What   weight  of   potassium   permanganate,  in 
acid  solution,  will  be  reduced  by  5000  cc.  of  hydrogen 
sulphide  at  standard  conditions  ? 

519.  Calculate  the  density  (referred  to  air)  of  C2H4. 

520.  (#)  The  vapor  density  of  chlorine  is  35,  the 
atomic  weight  is   35 ;  find  the  number  of   atoms  per 
molecule.     (6)   The  vapor  density  of  Zn  is  32.5,  its 
atomic  weight  is  65 ;  how  many  atoms  in  its  molecule  ? 
(<?)  Phosphorus  has  atomic  weight  31,  vapor  density  62. 
compute  as  before.     (d)  The  atomic  weight  of  ozone 
is  16,  its  vapor  density  is  24 ;  compute. 

521.  The  atomic  weight  of  copper  is  63.3  and  the 
formula  of  copper  chloride  is  CuCl2.    The  atomic  weight 
of  silver  is  108.     Determine  the  specific  heat  of  silver 
and  copper  respectively. 

522.  What  weight  of  ammonium  chloride  would  be 
required  in  order  to  prepare  5  Kl.  of  ammonia  ? 

523.  How   many  cc.   of  nitrogen  and  of  hydrogen 
would  be  produced  by  decomposing  20  cc.  of  ammonia 
by  means  of  electric  sparks  ? 

524.  What  volume  and  weight  of  air  would  contain 
enough  oxygen  to  burn  exactly  25  1.  of  hydrogen  ? 


214     PROGRESSIVE   PROBLEMS  IN   CHEMISTRY 

525.  What  volume  of  chlorine  would  be  required  to 
convert  20  1.  of  sulphur  dioxide  dissolved  in  water  into 
sulphuric  acid,  and  what  weight  of  sulphuric  acid  would 
be  produced  ? 

526.  An  iron  rod  250  cm.  long  at  -f  10°  C.  is  0.09 
cm.  longer  at   -f  40°  C. ;  what   will   its  length   be  at 
+  60CC.? 

527.  What  volume  of  chlorine  at  N.T.P.  would  be 
required  to  convert  an  acidified  solution  of  5  g.  of  crys- 
tallized ferrous  sulphate  into  a  ferric  salt? 

528.  How  many  cc.  of  a  solution  of  potassium  dichro- 
mate,  containing  50  g.  of  the  salt  per  1.,  would  be  re- 
quired to  oxidize  5  g.  of  ferrous  chloride  to  a  ferric  salt  ? 

529.  What  are  the  laws  of  diffusion  of  gases  ?     If  20 
volumes  of  hydrogen  take  10  minutes  to  diffuse  out  of 
a  vessel,  how  long  will  50  volumes  of  oxygen  take  to 
diffuse  out  under  like  conditions  ? 

530.  If  0.428  g.  of  one  of  the  oxides  of  manganese, 
when  heated  with  hydrochloric  acid,  gave  42   cc.   of 
chlorine,  at  N.T.P.,  which  oxide  of  manganese   was 
used  ? 

531.  Ferric  oxide  contains  30%   of  oxygen  and  its 
molecule  3  atoms  of  oxygen  ;    what   is  its  molecular 
weight  ? 

532.  If  1337  g.  of  copper  sulphate  yield  317  g.  of 
copper  and  its  molecular  weight  is  267.4,  how  many 
atoms  of  copper  are  there  in  a  molecule  of  the  sulphate  ? 

533.  A  sample  of  silver  nitrate  weighing  2.40  g.  was 
brought  into  solution  and  treated  with  a  soluble  chloride 
(excess).     The  weight  of   silver  chloride  precipitated 
was  2. 01  g.     What  was  the  purity  of  the  sample  ? 


SYSTEMATIC   REVIEW  215 

534.  What  weight  of  zinc  (98  %)  will  be  required  for 
the    liberation   of  the  hydrogen  from  10  g.   of  hydro- 
chloric acid  containing  39.1  %  of  HC1? 

535.  What    weight    of    sulphuric    acid     containing 
27.32  %   H2SO4  will  be  required  for  interaction  with 
2.17  g.  of  iron  wire  (99%  pure)? 

536.  On  the  top  of  a  mountain  the  barometer  stands 
at  70  cm.  and  the  temperature  is  +10°  C.,  while  in  the 
valley  the  barometer  stands  at  758  mm.  and  the  ther- 
mometer at  +  20°  C. ;  what  are  the  relative  densities  of 
the  air  in  the  two  places  ? 

537.  If  0.2815  g.  of  calcite  was  dissolved  in  30  cc.  of 
normal  HNO3,  and  the  excess  of  acid  determined  by 
normal  NaOH,  of  which  24.43  cc.  were  required,  what 
percentage  of  CO2  did  the  sample  contain? 

538.  If  2.0876  g.    of   hydrogen,  when  passed    over 
heated  oxide  of  copper,  yielded  18.7406  g.  of  water,  what 
is  the  equivalent  of  oxygen  ? 

539.  What  is  the  absolute   density  of  hydrogen  at 
+  20°  C.  and  740  mm.  pressure? 

540.  What  is  the  absolute  density  of  air  at  +10°  C. 
and  750  mm.  pressure?     The  absolute  density  at  the 
standard  conditions  is  1.293. 

541.  If  400   cc.   of   gas,  with   the    density    16,   and 
measured  at    +25°  C.    and   750  mm.  pressure,  are  to 
be  brought  to  a  temperature  of  +  10°  C.  and  a  pressure 
of  760  mm.,  what  weight  of  this  final  gas  can  be  con- 
tained in  a  vessel  of  100  cc.  capacity? 

542.  If  10  g.  of  a  gas,  measured  at  -48°  C.  and  600 
mm.  pressure,  were  expanded  by  heating  to  +  177°  C. 
and  reducing  the  pressure  to  480  mm.,  and  the  rarefied 


216      PROGRESSIVE   PROBLEMS   IN   CHEMISTRY 

gas,  250  cc.,  weighed  0.5  g.,  what  was  the  original  volume 
of  gas  and  what  was  the  density  of  the  gas  at  its  original 
and  final  volume  ? 

543.  If  10  1.  of  a  gas,  measured  at  +  20°  C.  and  750 
mm.  pressure,  weighed  14  g.,  what  weight  of  this  gas 
could  be  contained  in  a  smaller  vessel  holding  4  1.  at 
+ 10°  C.  and  760  mm.  pressure? 

544.  What  volume  will  1000  cc.  of  a  gas  at  -f  300°  C. 
and  740  mm.  pressure  occupy  when  reduced  to  standard 
conditions  ? 

545.  A  piece  of  metal  weighing  30  g.  displaced  20  cc. 
of   water;    what  is  the  relative  density  of  this  metal 
referred  to  water? 

546.  A  vessel  weighing  6.448  g.  weighed  7.963  g. 
when  filled  with  water  and  8.266  g.  when  filled  with  a 
salt  solution ;  what  is  the  relative  density  of  this  solu- 
tion referred  to  water? 

547.  What  is  the  relative  density  of  hydrogen  sul- 
phide referred  to  air  and  also  to  oxygen  ? 

548.  What  is  the  relative  density  of  hydrogen  chloride 
referred  to  hydrogen,  air,  oxygen  and  chlorine? 

549.  If  8  g.  of  oxygen  were  mixed  with  10.08  g.  of 
hydrogen,  and  both  gases  were  measured  at  the  stand- 
ard conditions,  what  was  the  relative  density  of  this 
mixture? 

550.  A   volume   of   gas,  with   the   relative   density 
0.8757,  was  found  to  measure  1560  cc.  when  transferred 
to  a  vessel  over  water  at  +  18°  C.  and  742.4  mm.;  what, 
is  the  weight  of  the  dry  gas  here  concerned? 

551.  What  volume  of  chlorine,  measured  at  + 10°  C. 
and  770  mm.   pressure,  would  be  required  to  convert 
5  g.  of  phosphorus  trichloride  into  the  pentachloride  ? 


SYSTEMATIC   REVIEW  217 

552.  What  weight  of  pure  sulphuric  acid  should  be 
obtained  from  100  tons  of  "pyrites"  containing  35  %  of 
sulphur  ? 

553.  The  coefficient  of  linear  expansion  of  iron  is 
0.000011 ;  how  much  must  an  iron  rod  40  ft.  long  be 
heated  to  expand  1  in.  ? 

554.  If  240  cc.  of  gas  at  a  pressure  of  740  mm.  were 
admitted  into  an  empty  vessel  of  800  cc.  capacity,  what 
was  the  pressure  of  the  gas  at  this  new  volume  ? 

555.  If  500  cc.  of  oxygen,  absolute  density  1.429, 
were  compressed  to  a  volume  of  125  cc.  at  constant 
temperature,  what  was  the  density  of  the  gas  at  this 
final  volume  ?     What  would  be  the  weight  of  50  cc.  of 
the  compressed  gas  ? 

556.  A  volume  of  gas  measured  1  ft.3  at  —  4°  F.  and 
30  in.  pressure ;  what  will  be  its  volume  at  -f-  68°  F. 
and  39.4  in.  pressure? 

557.  What  volume  of  liquid  carbon  dioxide,  measured 
at  0°  C.,  will  be  required  to  give  75  1.  of  the  gas  at  0°  C. 
and  760  mm.  pressure? 

558.  If  0.352  g.  of  a  sample  of  pyrolusite  was  heated 
with    hydrochloric   acid,   and  the   chlorine  which  was 
evolved  was  passed  into  a  solution  of  potassium  iodide, 
where  it  liberated  0.864  g.  of  iodine,  what  was  the  per- 
centage of  pure  MnO2  in  the  sample  ? 

559.  If  0.5  g.  of  pyrolusite  containing  92%  of  pure 
MnO2  was  heated  with  strong  hydrochloric  acid,  and 
the  resulting  chlorine  led  into  a  solution  of  potassium 
iodide,  what  amount  of  iodine  would  be  liberated  ? 

560.  If  35  cc.   of  a  solution  of  potassium  perman- 
ganate containing  15  g.  per  1.  were  required  to  oxidize 


218     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

50  cc.  of  acidified  solution  of  ferrous  sulphate  to  ferric 
sulphate,  what  was  the  amount  of  metallic  iron  in  a  1. 
of  the  ferrous  sulphate  solution  ? 

561.  What  volume  of  chlorine,  at  + 17°  C.  and  750 
mm.  pressure,  would  be  required  to  convert  6  g.  of  tin 
into  stannic  chloride  ? 

562.  A  volume  of  gas  weighing  5  g.  was  expanded  at 
a  constant  temperature  till  the   pressure  was  reduced 
to  |  of  its  former  value,  and  500  cc.   of  the  rarefied 
gas  weighed  1.25  g.     What  was  the  original  volume 
of     the    gas  ?     Calculate    also    the    original    density, 
assuming  the  original   observations  made  at  standard 
conditions. 

563.  A  volume  of  gas  measuring  600  cc.  at  760  mm. 
pressure  was  expanded  to  a  volume  of  1000  cc.  at  con- 
stant temperature ;  what  was  the  final  pressure  of  the 
gas? 

564.  A  solution  contains  48  g.  of  Pb  (NO3)2  per  1.; 
how     much     H2SO4    will     10     cc.     of     this     solution 
precipitate  ? 

565.  Calculate  the  volume  of  chlorine  liberated  in  the 
action  of  40  g.  of  potassium  dichromate  upon  a  hydro- 
chloric acid  solution. 

566.  If  0.535  g.  of  a  sample  of  pyrolusite,  when  acted 
on  with  a  mixture  of  sulphuric  acid  and  oxalic  acid, 
produce  0.48  g.  of  carbon  dioxide,  what  was  the  per- 
centage of  pure  MnO2  in  the  sample  ? 

567.  The  absolute  density  of  oxygen  is  1.429.     When 
a  given  volume  of  this  gas  is  warmed  from   0°C.   to 
+  40°  C.  under  a  constant  pressure,  what  will  the  abso- 
lute density  of  the  gas  become  ? 


SYSTEMATIC   REVIEW  219 

568.  A  volume  of  gas  with  the  absolute  density  4  and 
measuring  250  cc.  at  0°  C.  was  expanded  by  warming, 
under  constant  pressure,  to  a  volume  of  600  cc.     What 
increase  in  temperature  was  required,  and  what  would 
be  the  weight  of  300  cc.  of  the  rarefied  gas  ? 

569.  If  500  cc.    of  a  gas,  the   absolute   density  of 
which  is  6,  must  be  reduced  to  a  density  of  0. 75  at  con- 
stant temperature,  what  will  be  the  volume  of  this  rare- 
fied gas  ?     Calculate  also  the  weight  of  400  cc.  of  the 
rarefied  gas. 

570.  Calculate    the    relative    density   of    hydrogen 
chloride,  5  1.  of  which  under  standard  conditions  weigh 
8.205  g. 

571.  Calculate  the  relative  density  of  chlorine,  100 
cc.  of  which  at  standard  conditions  weigh  0.322  g. 

572.  The  sp.  gr.  of  chlorine  is  2.449;  what  is  its  rel- 
ative density  upon  the  oxygen  standard? 

573.  What  is  the  weight  of    BaO  in   1.9327  g.    of 
BaCr04  ? 

574.  What   is   the  weight  of  CaO  in   2.9478  g.   of 
CaS04? 

575.  What   weight   of    MnCO3    yields    on    ignition 
1.450  g.  of  Mn3O4  ? 

576.  How  much  arsenic  is  there  in  5  g.   of  As2S3  ; 
of  As2S5  ;  of  Mg2As2OT  ? 

577.  How  much  Agl  can  be  made  from  a  Ib.  of  pure 
silver  ;  how  much  AgBr  ;  how  much  AgCl  ? 

578.  If  1.10  g.  of  stibnite  gave  on  analysis  0.5987  g. 
of  Sb2O4,  what  was  the  percentage  of  antimony  ? 

579.  Air  liquefies  at  —  182°  C.     Express  this  temper- 
ature on  the  Fahrenheit  scale. 


220     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

580.  When  water  in  an  open  dish  boils  at  -f  209°  F., 
what  would  be  the  reading  of  an  accurate  barometer 
placed  near  by  ? 

581.  Reduce  12  1.  of  oxygen,  measured  at +47°  C. 
and  under  a  pressure  of  782  mm.    of  mercury,  to  the 
standard  conditions. 

582.  What  will  be  the  volume  of  9  1.  of  hydrogen 
when  heated  to  +  120°  C.  and  under  a  pressure  of  423 
mm.? 

583.  Given  27  cc.  of  nitrogen  at  + 14°  C.  and  752.1 
mm.,  what  will  be  its  volume  at  -f  20°  C.  and  767.8 
mm.? 

584.  What  is  the  weight  of  77.2  cc.  of  air,  measured 
over  water  at  +  27°  C.  and  758  mm.  pressure  ? 

585.  What  is  the  weight  of  17  1.  of  Irydrogen,  meas- 
ured at  +  12°  C.  and  3  atmospheres  pressure  ? 

586.  What  is  the  weight  of  85  cc.  of  NH3,  measured 
over  mercury  at  + 140°  C.  and  under  a  pressure  of  770 
mm.?     Given  the  tension  of  mercury  vapor  at  +  140°  C. 
=  1.76  mm. 

587.  Find  the  density  referred  to  air  of  chloroform 
vapor,  given  the  following  data  for  Dumas'  method  : 
weight  of  bulb  and  air  at  +  20.5°  C.  and  763.9  mm.  = 
34.8451  g. ;  weight  of  bulb  and  vapor  at  +  116.5°  C.  and 
763.9   mm.  =  35.8430   g.;    volume   of   air   in   bulb   at 
+  20.5°  C.  =  394.93  cc. 

588.  An  object,  the  sp.  gr.  of  which  is  3.38,  weighed 
39.7250  g.  in  air  when  weighed  with  brass  weights; 
what  is  its  true  weight  ? 

589.  An  object,  the  sp.  gr.  of  which  is  0.95,  weighed 
17.8540  g.  in  air  when  weighed  with  brass  weights; 
what  is  its  true  weight  ? 


SYSTEMATIC   REVIEW  221 

590.  A  bar  of  gold,  sp.  gr.  =  19.3,  weighed  10.73685 
Kg.  when  weighed  in  air  with  brass   weights;    what 
is  the  true  weight  ? 

591.  A  piece  of  pyrrhotite,  sp.  gr.  =  4.58,  weighed  in 
air  47.3854  g.  when  weighed  with  platinum  weights ; 
what  is  its  true  weight  ? 

592.  A  piece  of  antimony,   sp.   gr.  =6.71,  weighed 
75  g.  in  air,  the  weights  used  being  50  g.  brass,  20  g. 
and  5  g.  platinum ;  what  is  the  true  weight  ? 

593.  If  50  cc.  of  CH4,  50  cc.  of  H2,  and  50  cc.   of 
C2H2  were  mixed  with  450  cc.  of  oxygen  and  exploded, 
what  would  be  the  resulting  volume  at  the  same  tem- 
perature and  pressure,?  (Assume  that  the  temperature  is 
below  +  100°  C.) 

594.  How  many   amperes   are    flowing  in  a  circuit 
which,  in  the  course  of  1  hr.  and  15  min.,  has  deposited 
30.186  g.  of  silver? 

595.  How  many  g.  of  lead  shot  at  +  200°  F.  must  be 
used  to  raise  the  temperature  of  400  g.  of  water  from 
+  40°F.  to  +90°F.? 

596.  How  much  alcohol  at  — 10°  C.  must  be  mixed 
with  200  g.  of  chloroform  at  +  30°  C.,  that  the  final 
temperature  may  be  +  10°  C.? 

597.  If  a  50  g.  lump  of  silver,  left  in  ice  water  until 
it  is  cooled  to  0°  C.,  is  dropped  into  100  g.  of  ether 
at  -h  30°  C.,  what  will  be  the  temperature  of  the  mixture  ? 

598.  We  have  at  our  command  a  waste  acid  from  the 
nitrating  of  glycerine,  the  composition   of    which  is  : 
sulphuric   acid,    62.18%;    nitric    acid,    19.07%;    and 
water,  18.75%.     We  also  have  an  oil  of  vitriol  contain- 
ing 97  %  by  weight  of  H2SO4,  and  a  commercial  nitric 


222     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

acid  containing  87%  by  weight  of  HNO3.  What 
weights  of  each  must  be  taken  to  give  1000  Ib.  of  a 
mixture  containing  60%  of  H2SO4,  28%  of  HNO3, 
and  17  %  of  water,  without  adding  water  ? 

599.  Bearing  in  mind  that  the  molecule  of  mercury 
vapor  is  monatomic,  calculate  the  weight  of  500  cc.  of 
that  gas. 

600.  If  we  have  two  alloys,  viz.,  a  brass  containing 
65  %  of  copper  and  35  %  of  zinc,  and  a  German  silver 
containing  56  %    of  copper,  24  %  of  zinc,  and  20  %  of 
nickel,  supposing  that  there  is  no  loss  by  oxidation  or 
volatilization  during  the  fusion,  what  will  be  the  com- 
position of  the  alloy  formed  by  melting  these  two  alloys 
together  in  such  proportion  that  it  contains  30  %  of  zinc  ? 

601.  Suppose  that  we  desire  to  prepare  100  Ib.  of  an 
alloy  containing  70  %  of  copper,  20  %  of  zinc,  and  10  % 
of  tin  ;  we  have  at  our  command,  pure  copper,  a  brass 
containing  |  copper  and  J  zinc,  and  a  solder  containing 
J  zinc  and  J  tin  :  how  much  of  each  must  be  taken  ? 

602.  Given  pure  silver  and  an  alloy  containing  890 
parts  of  silver  and  110  parts  of  copper,  how  many  oz. 
of  each   must  be  taken  to  form  1000  oz.  of   an  alloy 
containing  925  parts  of  silver  and  75  parts  of  copper  ? 

603.  Given  a  mixture  of  silver  chloride  and  silver 
bromide,  the  weight  of  which  is  1.5  g.,  analysis  showing 
the  mixture  to  contain  1  g.  of  metallic  silver,  what  are 
the  weights  of  the  chlorine  and  of  the  bromine  in  the 
mixture  ? 

604.  The  analysis  of  a  dolomite  gave  2  %  of  silica, 
and  the  remainder  was  calcium  and  magnesium  carbon- 
ates.      The  determination  of   magnesia  gave  10  %  of 
MgO.     What  was  the  percentage  of  carbon  dioxide  ? 


SYSTEMATIC   REVIEW  223 

605.  How  many  ft.3  of  air  at  +  70°  C.  are  needed  for 
the  combustion  of  1  Ib.  of  a  coal  having  the  analysis : 
carbon,  90%;    hydrogen,  5%;    oxygen,   3.5%;    nitro- 
gen, 0.1%;    sulphur,  0.5%.       Assume  the  factor  for 
excess  as  2. 

606.  Calculate  the  number  of  ft.3  of  air  at  +  60°  F. 
needed  for  the  combustion  of  1  ton  of  a  coal  having 
the  composition:    carbon,  74.60  %;  hydrogen,  4.89%; 
oxygen,  6.90%.     Assume  the  factor  for  excess  as  1.5. 

607.  How  many  calories  are  required  to  raise  500  g. 
of  a  substance  of  specific  heat  0.5  from   +15°  C.  to 

+  37°C.? 

608.  How  many  g.  of  hot  water  at  4-  100°  C.  must  be 
poured  into  3  1.  of  cold  water  at  +  4°  C.  to  warm  it  to 
+  20°  C.  ? 

609.  When  200  g.  of  hot  water  at  +  80°  C.  are  poured 
into  a  pail  of  water  at  + 14°  C.,  the  temperature  of  the 
mixture  becomes  +  20°  C.     How  many  g.  of  cold  water 
must  there  have  been  in  the  pail  at  first  ? 

610.  If  80  g.  of  water  at  + 100°  C.  are  poured  into 
80  g.  of  water  at  + 10°  C.,  what  will  be  the  tempera- 
ture of  the  mixture  ? 

611.  If  500  g.  of  water  at  4-  90°  C.  are  poured  into 
600  g.  of  water  at  +  30°  C.,  what  will  be  the  resulting 
temperature  ? 

612.  One  Kg.  of  copper  at  4- 100°  C.,  when  plunged 
into  600  g.  of  water  at  + 10°  C.,  raises  the  temperature 
of  the  water  to  +  22°  C.      Find  the   specific   heat  of 
copper. 

613.  Find  the  water  equivalent,  or  thermal  capacity, 
of  a  brass  calorimeter  weighing  92  g. 


224      PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

614.  How  many  g.  of  mercury  at  -f-  98°  C.  must  be 
poured  into  100  g.  of  water  to  raise  its  temperature 
from  +  5°  C.  to  +  18°  C.  ? 

615.  How  many  calories  of  heat  are  required  to  raise 
the  temperature  of  (a)  5  g.  of  water  +  10°  C. ;  (5)  8  g. 
of  zinc  +20°  C.? 

616.  How  many  calories  of  heat  are  given  out  (a) 
when  2  Kg.  of  water  cools  +  90°  C.  ;    (£>)  when  700  g. 
of  copper  cools  from  -f  250°  C.  to  +  140°  C.? 

617.  If  500  g.  of  water  at  +  5°C.  and  500  g.  of  mer- 
cury at  0°  C.  are  each  given  the  same  quantity  of  heat, 
how  hot  will  the  mercury  become  when  the  water  has 
been  heated  to  +  10°C.? 


CHAPTER   XIV 

A  Progressive  Series  of  Problems  based  on  Equa- 
tions taken  from  a  recent  text-book  on 
General  Inorganic  Chemistry 

1.  If  63  g.  of  sodium  react  with  hydrogen  monox- 
ide, what  is  the  weight  of  gas  evolved? 

2.  If  32  g.   of  muriatic  acid  are  treated  with  zinc, 
how  many  g.  of  salt  are  produced  ? 

3.  Zinc  is  boiled  with  caustic  soda  solution  and  10  1. 
of  a  gas  are  given  off.     Find  weight  of  zinc  and  caustic 
soda  used. 

4.  A  solution  containing  27  g.  NaOH  is  heated  with 
an  excess  of   zinc.      Find  weight  and  volume  of   gas 
produced. 

5.  What  weight  of  oxygen  and  what  other  compo- 
nent is  required  to  make  100  g.  of  BaO2  ? 

6.  Sodium  peroxide,  when  added  to  water,  liberates 
10  1.  of  oxygen  at  +  6°  C.  and  662  mm.     Find  weight 
of  NaOH  produced. 

7.  What  volume  of  ozone  can  be  made  from  300  g. 
of  oxygen  ? 

8.  What  weight  of  water  is  required  to  decompose 
completely  23  g.  of  Na2O2? 

9.  What  weight  of  NaOH  can  be  made  from  200  g. 
of  sodium  monoxide  ? 

225 


226      PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

10.  On   heating  392  g.  of    copper  hydroxide,  what 
weights  of  products  do  you  get  ? 

11.  Into  how  many  g.  of  the  resultant  gases  do  222  1. 
of  HC1  decompose  ? 

12.  In  the  synthesis  of  100  g.   of  table  salt,  what 
weights  of  the  components  are  used  and  what  volume  of 
the   gaseous  constituent   is   needed   at   |   atmospheric 
pressure  and  a  temperature  of  + 10°  C.  ? 

13.  What  volume  of  HC1  is  needed  to  produce  30  g. 
of  MnCl2? 

14.  What  weight   and   volume    of   oxygen    will   be 
needed  to  liberate  102  m.3  of  chlorine  from  muriatic 
acid? 

15.  We  need  2  tons  of  bromine.     What  weight  of 
chlorine  is  required  and  how  much  NaCl  will  be  pro- 
duced? 

16.  If  110  g.  of  Nal  are  decomposed  by  chlorine, 
what  are  the  weights  of  the  products,  and  what  is  the 
volume  of  chlorine  at  +  300°  C.  and  663  mm.? 

17.  If  222  1.  of  chlorine  are  dissolved  in  water  and 
exposed  to  the  sun,  what  weights  of  materials  will  be 
left  after  complete  decomposition? 

18.  How  much  KOH  would  be  needed  to  make  79  g. 
of  KC1? 

19.  Fluorine  and  water  gave  63  1.  of  HF  at  0°  C. 
and  771  mm.     Find  volume  of  fluorine  used  at  —  10°  C. 
and  621  mm. 

20.  NaCl  +  H2SO4  will  give  either  sodium  sulphate 
or  sodium  hydrogen  sulphate  according  to  the  tempera- 
ture.    If  100  g.  of  H2SO4  are  used  in  either  case,  what 
weight  of  salt  will  be  required? 


PROBLEMS  BASED  ON  EQUATIONS     227 

21.  NaBr  will  give  what  volume  and  weight  of  HBr 
when  treated  with  16  g.  of  H3PO4? 

22.  PBr3  with  100  g.  of  H2O  will  give  what  weights 
and  what  volume  of  gaseous  product? 

23.  Of  phosphorus  10  lb.,  of  bromine  6  lb.,  and  of 
water  1  lb.  are  mixed.     After  complete  reaction,  what 
weights  of  products  and  of  excess  do  you  get? 

24.  If  20  g.  of  HKF2  decompose,  what  weights  of 
wrhat  substances  result? 

25.  What  weight  of  fluorspar  will  give  10  lb.  of  CaSO4 
when  treated  with  oil  of  vitriol?     What  volume  of  gas 
will  result  at  —40°  C.  and  2  atmospheres  pressure? 

26.  An  iron  ore  is  60  %  silica.     What  weight  of  sam- 
ple was  taken  if  it  requires  20  1.  of  HF  to  decompose  it? 

27.  The  decomposition  of  2  lb.  LiCl  will  give  how 
many  1.  of  chlorine  at  —  1°  C.  and  600  mm.  ? 

28.  To  make  1  Kg.  of  potassium,  what  weight  of  car- 
bon and  K2CO3  will  be  needed,  and  what  volume  of  gas 
will  be  evolved? 

29.  What  weight  of  ammonium  salt  is  required  by 
13  1.  of  nitrogen  at  +112°  C.  and  300  mm.  ? 

30.  What  weight  of   NH4NO3  will   yield   21   1.   of 
laughing  gas  at  standard  conditions? 

31.  In  the  synthesis  of  30  g.  of  ammonia,  what  vol- 
ume of  the  components  will  be  needed  at  + 13°  C.  and 
900  mm.  ? 

32.  What  weight  of  water  is  required  by  10  g.  of 
Mg3N2  for  complete  decomposition,  and  what  volume 
of  gas  will  be  evolved  ? 

33.  NH4OH,  on  breaking  up,  gives  3  1.  of  NH3  at 
0°  C.  and  760  mm.     Find  weight  of  hydroxide  used. 


228     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

34.  Sal-ammoniac   is   treated  with  10  g.  of   KOH. 
Find  weights  of  resulting  compounds. 

35.  If  20  g.  of  potassium  and  enough  ammonia  inter- 
act, what  weight  and  volume  of  hydrogen  is  produced? 

36.  What  weight  of  salt  is  given  by  300  cc.  of  HC1 
+  NH3? 

37.  Lime  water  treated  with  10  1.  of  CO2  at  standard 
conditions  will  give  what  weight  of  precipitate  ? 

38.  How  much  acid  calcium  carbonate  can  be  pro- 
duced from  1  Ib.  of  slaked  lime  and  sufficient  CO2? 

39.  A14C3  on  treatment  with  12  Kg.  of  water  will 
give  what  volume  of  CH4  and  what  weight  of  precipi- 
tate? 

40.  To   produce  3000  cc.  of  CH4,  what  weight  of 
sodium  acetate  would  be  needed  ? 

41.  What  volume  of  oxygen  would  be  needed  to  burn 
300  cc.  of  marsh  gas  ? 

42.  If  2  1.  of  oxygen  are  heated  with  carbon,  what 
volume  of  gas  is  produced  at  |  atmospheric  conditions  ? 

43.  If  100  Ib.  of  chalk  are  treated  with  HC1,  what 
weight  of  water  will  be  produced  ? 

44.  Magnesium  is  burned  in  a  flask  containing  20  1. 
of  choke  damp  at  0°  C.  and  760  mm.     Find  weight  of 
magnesium  used  and  of  carbon  liberated. 

45.  To  produce  20  1.  of  CO,"  what  weights  of  sub- 
stances are  needed  ? 

46.  Carbon  is  heated  with  100  g.  of  oxygen.     Find 
the  weight  of  the  product. 

47.  How  much  H2O  and  CO2  will  be  needed  to  pro- 
duce a  gram  molecule  of  formic  acid  ? 


PROBLEMS  BASED  ON  EQUATIONS     229 

48.  One  ton  of   coke  and  steam  reacting  will  give 
what  volume  of  gas  at  -f- 10°  C.  and  777  mm.  ? 

49.  If  800  cc.  of  CO  are  passed  over  heated  CuO, 
what  weight  of  copper  is  left  ? 

50.  In  the  reduction  of  100  tons  of  hematite,  what 
weight  of  CO  will  be  needed  and  what  weight  of  metal 
will  result  ? 

51.  K2S5  +  100  g.  of  HC1  will  give  what  weight  of 
sulphur;   what  volume  of  gas  ? 

52.  Ca3(PO4)2  +  3  SiO2  +  5  C  =  3  CaSiO3  +  5  CO  + 
2  P.    Find  weights  of  products  when  3  Kg.  of  C.  are 
used ;  find  volume  of  CO  at  -  40°  C.  and  1000  mm. 

53.  Arsenopyrite  is  roasted  with  10  g.   of  oxygen. 
Find  volume  of  gas  evolved  and  As2O3  produced. 

54.  In  the  reduction  of  200  g.   of  poisonous  flour, 
wkat  weight  of  metal  is  produced  ? 

55.  What   weights    of  materials  will  be  needed  to 
produce  100  Ib.  of  antimony  ? 

56.  One  Kg.  sodium  reacts  on  BaCl2.     Find  weight 
of  common  salt  produced. 

57.  We  need  200  g.  of  boron;  what  weight  of  the 
oxide  and  sodium  will  be  needed  ? 

58.  What  weight  of  magnesium  must  be  used  to  re- 
duce 10  Kg.  of  B2O3  ? 

59.  What  weight  of  aluminum  can  be  made  from  the 
double  halogen  salt  of  aluminum  when  treated  with 
100  g.  of  sodium? 

60.  In    the    Goldschmidt    alumino-thermic    process, 
what  weight  of  materials  must  be  used  to  give  100  Ib. 
of  iron  ? 


230     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

61.  If  10  g.  of  aluminum  are  treated  (a)  with  HC1 ; 
(£)  with  NaOH ;   (<?)  with  KOH,  what  is  the  weight  of 
products  in  each  case  ? 

62.  If  300  Ib.  of  sand  are  heated  with  carbon,  how 
much  silicon  will  result ;  what  volume  of  gas  at  +81°  C. 
and  |  atmosphere  ? 

63.  If  100  1.  of  CO  are  produced  in  the  reduction  of 
SiO2  with  C,  what  is  the  weight  of  metal  freed  ? 

64.  What  volume  of  hydrogen  at  2  atmospheres  and 
-  10°  C.  can  be  made  from  300  g.  of  tin,  and  HC1  ? 

65.  What  weight  of  tin  oxide  can  be  made  by  heating 
20  g.  of  tin  in  air  ? 

66.  If  400  g.  K2SnO8  are  made  from  tin,  H2O  and 
KOH,  what  is  the  weight  of  each  substance  used  ? 

67.  What  volume  of  chlorine  is  needed  to  make  300 
g.  of  SnCl4  from  SnCl2  ? 

68.  Galena  heated  with  1  Kg.   of  oxygen  will  give 
what  volume  of  SO2  ;  what  weight  of  litharge  ? 

69.  What  weight  of  lead  heated  with  air  will  produce 
10  Ib.  of  lead  monoxide?     Find  volume  of  air  used. 

70.  When  30  g.  of  litharge  and  sufficient  galena  are 
heated  together  to  produce  the  metal,  what  weight  of 
products  will  they  give? 

71.  If  10  g.  of  HC1,  20  g.  of  NaOH  and  30  g.  of 
KOH  each  react  on  zinc,  what  in  each  case  is  the  weight 
of  the  product  ? 

72.  Hematite  is  reduced  by  hydrogen.     What  weight 
of  iron  can  be  made  from  100  g.  of  ore  ? 

73.  If  100  g.   of  cinnabar  are  roasted  in  air,  what 
weight  of  quicksilver  results  ? 


PROBLEMS  BASED  ON  EQUATIONS    231 

74.  Iron   and    CO    interact.     Find    weight   of   iron 
needed  to  give  100  1.  of  oxygen. 

75.  If  600  g.  of  H2O2  are  made  from  Ba2O2,  what 
weight  of  oil  of  vitriol  is  needed  ? 

76.  One  1.  of  ozone  with  H2O2  gives  what  volume  of 
oxygen  ? 

77.  Ag2O   and   100  g.    of  H2O2  will  liberate  what 
weight  of  oxygen  and  of  silver  ? 

78.  What  weight  of  iron  sulphide  will  make  20  1.  of 
H2S? 

79.  Calcium  phosphide  treated  with  100  g.  of  muri- 
atic acid  will  liberate  what  volume  of   phosphine  at 
+  1°C.  and  766  mm.? 

80.  KOH  +  P4+  3  H2O  =  3  KH2PO2  +  PH3.     What 
weight  of  KOH  and  of  P  are  needed  to  give  (a)  100 
g.  of  PH3;   (6)  31  1.  of  PH3  at  +8°  C.  and  861  mm.? 

81.  5  P2H4  =  6  PH3  +  P4H2.      Find  weight  of  P4H2 
produced  when  17  g.  of  PH3  is  liberated  at  -f 13°  C. 
and  750  mm.? 

82.  Arsenic  is  made  from  3  g.  of  As2O3  and  carbon. 
How  much  carbon  is  needed? 

83.  SiMg2  +  4HCl=2MgCl2  +  SiH4.     If  30  g.  of 
HC1  are  used,  find  weights  of  the  other  factors  in  the 
equation. 

84.  If  30  g.  ZnCl2  are  made  from  ZnO,  what  is  its 
weight  ? 

85.  3  C12  +  A12O3  +  3  C  react.     Find  weight  of  A1C18 
and  volume  of  carbon  monoxide  if  10  g.  of  Cl  are  used. 

86.  Zinc  is  acted  on  by  20  1.  of  chlorine.     What 
weight  of  salt  is  produced  ? 


232     PROGRESSIVE   PROBLEMS  IN   CHEMISTRY 

87.  A  lunar  caustic  solution  containing  20  g.  is  treated 
with  a  "  salt "  solution.     Find  weight  of  residue  left  in 
solution  after  filtering. 

88.  If  100  g.  of  iron  are  treated  with  600  g.  of  iodine, 
what  weight  of  the  iron  iodide  is  made  ? 

89.  In  the  following  equation,  if  1  Kg.  of  AgBr  is 
used,  find  the  weight  of  the  missing  compound: 
3FeCr204  +  2  AgBr  +  Ag2Br  =  Fe2(Cr2O4)3  +  ?  +  4  Ag. 

90.  NaAuCl4  +  3  Ag  =  NaCl  +  3  AgCl -f-  Au.    In  this 
equation  calculate  the  weight  of  gold  when  100  g.  of 
silver  are  used. 

91.  1  g.  BC13  +  water  =  what  volume  of  gas  and  what 
weight  of  B(OH)3? 

92.  Fire  damp  and  chlorine  interact,  producing  tetra- 
chlormethane  and  10  1.  of  ,HC1.     Find  weights  of  the 
first  two  substances. 

93.  100  g.   CC14  +  H2O  =  what  volume  of   CO2  at 
+  33°C.  and  555  mm.? 

94. '        SiCl4  +  4  H20  =  4  HC1  +  Si(OH)4. 

30  g.  +  80  g.  ?  ? 

Find  weights  of  the  products  and  excess. 

95.  SiO2  and  HF  interact.     If  30  g.  of  H2O  are  pro- 
duced, find  the  volume  of  HF  used  at   -f  60°  C.  and 
760  mm. 

96.  1  g.  silicon  fluoride  is  passed  into  an  excess  of 
water.    What  volume  of  gas  and  weight  of  solid  is  left  ? 

97.  What  weight  of  metastannic  acid  is  given  by  3  g. 
of  stannic  chloride  with  water  ? 

98.  What  weights  of  SiF4  and  water  result  in  the 
production  of  90  g.  of  H2SiF6  ? 


PROBLEMS  BASED  ON   EQUATIONS          233 

99.    TiCl4  +  water  =  what  weight  of  TiOC]2  when 
2  1.  of  HC1  are  given  off  ? 

100.  To  produce  30  g.  of  H2SnO3,  what  weight  of 
SnCl4  was  used  ? 

101.  One  1.  of  lead  nitrate  solution  is  treated  with 
20  g.  of  salt  and  a  complete  precipitation  occurs.     Find 
the  percentage  of  lead  salt  in  the  solution. 

102.  What  weight  and  what  volume  of  chlorine  is 
liberated  by  100  g.  of  PbO2  +  HC1  ? 

103.  PC13,  AsCl3,  BiCl3  and  SbCl3  +  excess  of  water 
=  what  weight  of  the  oxy chlorides  when  4  1.  of  HC1 
are  liberated  in  each  case  ? 

104.  10  g.  PC13     +  3  H2O  =  3  HC1  +  ? 
10  g.  PC15     +    H20  =  2  HC1  +  ? 
10  g.  POC13  +  3  H2O  =  3  HC1  +  ? 
10  g.  PC16     +  4  H2O  =  5  HC1  +  ? 

In  these  equations  find  the  weight  of  the  compound 
formed  in  each  case. 

105.  2  CuSO4  +  K4Fe(CN)6  =  Cu2Fe(CN)6  +  ? 

If  100  g.  of  K4Fe(CN)6  are  taken,  what  weight  of 
bluestone  is  used,  and  what  weight  of  the  missing  term 
is  produced? 

106.  Copper  heated  with  1  m.3  of  air  will  yield  what 
weight  of  oxide  ? 

107.  2  Kg.  of  P2O6  contain  what  weight  of  P  and 
what  volume  oxygen  ? 

108.  A  3  1.  flask  of  O  acts  on  ZnS.     Find  the  weight 
of  products. 

109.  On  roasting  800  g.  of  As2S3,  what  volume  of  O 
is  needed  and  what  volume  of  gas  is  produced  ? 


234      PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

110.  If  100  g.  of  CuSO4  in  solution  are  treated  with 
a  solution  of  KOH  and  the  precipitate  is  heated,  what 
weight  of  products  results  ? 

111.  Limestone  is  heated  till  all  the  gas  is  driven  off. 
It  measures  109  1.     Calculate  the  weight  of  gas  and  of 
oxide  produced. 

112.  What  weight  of  oxide  and  of  water  is  formed 
by  20  g.  of  B(OH)3? 

113.  Lime  -f-  300  Ib.  of  water  =  what  weight  of  cal- 
cium hydroxide  ? 

114.  P2O5  and  H2O  interact  and  form  100  g.  of  ortho- 
phosphoric  acid.     Find  weight  of  P2O5  and  volume  of 
H2O  at  0°  C.  and  760  mm. 

115.  What  weight  and  volume  of  H  are  liberated  by 
2  Kg.  of  sodium  thrown  on  water  ? 

116.  Ferric  chloride  +  30  cc.  of  NaOH  solution  (50  % ) 
will  yield  what  weight  of  precipitate  ? 

117.  Sulphuric  anhydride  +  a  ton  of  water  produce 
what  weight  and  volume  of  acid  ?     (Sp.  gr.  of  H2SO4 
=  1.84.) 

118.  What  weight  of  Na2O  and  of  H2O  are  required 
to  produce  100  g.  of  NaOH  ? 

119.  What  weight    of   NaOH  will   be   required   to 
neutralize  300  cc.  N/2  H2SO4  solution? 

120.  Na2O  4- 100  g.  of  water  will  form  what  weight 
of  caustic  soda  ? 

121.  What  weight  of  CuS  will  be   precipitated  by 
27  1.  of  H2S  at  +  20°  C.  and  667  mm.  from  excess  of 
copper  solution  ? 

122.  Green  vitriol  -f  (NH4)2S  give  100  g.  of  FeS. 
Find  weights  of  substances  used. 


PROBLEMS  BASED  ON  EQUATIONS    235 

123.  Muriatic  acid  in  excess  reacts  on  100  g.  of  FeS. 
Find  volume  of  gas  evolved  at  — 13°  C.  and  500  mm. 

124.  To  slake  1  ton  of  lime  what  volume  of  water  at 
0°  C.  would  be  needed,  and  what  weight  of  Ca(OH)2 
would  be  produced  ? 

125.  From  1000  Kg.  of  Na2CO3,  what  weight  of  NaOH 
can  be  made  ? 

126.  To  produce   100  1.  of  oxygen  what  weight  of 
Na2O2  would  be  needed  and  what  volume  of  H2O  in 
cc.  would  be  used  ? 

127.  Na2SO4  +  C  =  what  weight  of  products,  if  3  Kg. 
of  carbon  are  used  ? 

128.  H2S  and  3  g.  of  potassium  will  liberate  what 
volume  of  gas  at  +  20°  C.  and  777  mm.  ? 

129.  CuO  +  100  g.  of  H2SO4  will  yield  what  weight 
of  water  ? 

130.  CuCl2  with  caustic  soda  solution  containing  50 
g.  yields  what  weight  of  Cu(OH)2  ? 

131.  On  boiling  300  g.  of  copper   hydroxide  with 
water,  what  weights  of  materials  result  ? 

132.  CuOH  on  being  heated  yields  10  g.  of  Cu2O ; 
what  weight  of  water  will  be  formed  ? 

133.  AuO,OH  +  NaOH  =  H2O  +  NaAuO2.      If  41 
g.  of  NaOH  are  used,  what   weight  of  NaAuO2  will 
result  ? 

134.  A  bin  of  lime  is  treated  with  10  tons  of  water, 
which  just  slakes  it.     A  house  is  plastered  with  this 
lime   made    into   mortar.      Find   the    volume    of    CO2 
needed  to  convert  all  the  mortar  into  CaCO3. 

135.  CaSO4  on  being  heated  with  2  Kg.  of  carbon 
yields  what  weights  of  materials  ? 


236     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

136.  When  30  g.  of  ZnSO4  are  treated  with  NaOH 
solution,  they  will  yield  (a)  what  weight  of  Zn(OH)2  ; 
(6)  what  weight  of  compound  when  NaOH  is  used  in 
excess  ? 

137.  Mercurous  nitrate  with  30  g.  of  NaOH  gives 
what  weight  of  Hg2O  ? 

138.  Hg2O  on  exposure  to  light  yields  30  g.  of  mer- 
cury.    Find  weight  of  Hg2O  used  and  of  residue  other 
than  Hg  left. 

139.  H2S  is  passed  into  a  solution  containing  100  g. 
of  HgCl2.     What  volume  of  gas  is  used  to  bring  about 
complete  precipitation  ? 

140.  KI  solution  containing  30  g.  reacts  on  (a)  HgNO3 
solution  ;   (b)  Hg(NO3)2  solution.     Find  weight  of  re- 
sulting salt  in  each  case. 

141.  NH4OH,  when  mixed  with  20  g.  of  A12(SO4)3  in 
solution,  yields  how  many  g.  of  residue  ? 

142.  A12(SO4)3  + 100  g.  (NH4)2S  will  produce  what 
weight  of  the  sulphide  of  the  metal? 

143.  A12S3  +  excess  of  water  gives  200  g.  of  A1(OH)3. 
Find  weight  of  A12S3. 

144.  In  the  Le  Blanc  process  what  weight  of  mate- 
rials can  be  made  from  300  Kg.  of  common  salt? 

145.  Sodium   sulphide   with   200   Kg.  of   powdered 
limestone  produces  what  weight  of  CaS? 

146.  From    10,000   1.  of  NH3  -f  sufficient   CO2  and 
water,  how  many  Kg.  of  sodium  dicarbonate  may  be 
produced? 

147.  Washing  soda  +  water  and  3000  1.   of  CO2  at 
—  8°  C.  and  900  mm.  will  produce  what  weight  of  the 
dry  product? 


PROBLEMS   BASED   ON   EQUATIONS          237 

148.  Bicarbonate  of  soda  with  30 1.  of  HC1  will  gener- 
ate what  volume  of  gaseous  product? 

149.  Silver  nitrate  with  21  g.  of  Na2CO3  gives  what 
weight  of  precipitate  ? 

150.  Washing  soda  reacting  on  1  Kg.  of  sugar  of  lead 
will  throw  down  what  weight  of  residue  in  solution  ? 

151.  3  PbC03  +  H20  =  Pb3(C03)2(OH)2  +  C02.     If 
500  1.  of  CO2  are  liberated,  what  is  the  weight  of  basic 
salt  produced? 

152.  What  volume  of  HF  will  be  needed  to  use  up 
20  g.  of  quartz,  and  what  weight  of  gas  will  be  pro- 
duced? 

153.  Na4SiO4  is  made  from  SiO2  and  300  g.  of  Na2O. 
What  weight  of  Na4SiO4  was  produced  ? 

154.  K4SiO4,  on  treatment  with  200  1.  of  HC1,  pro- 
duces what  weight  of  orthosilicic  acid  and  of  KC1? 

155.  Sodium  sulphide  + 100  g.  of  SnS2  =  Na2SnS3. 
Find  weight  of  Na2S. 

156.  Copper  +  2  Kg.  of  aqua  fortis  will  yield  what 
weight  of  Cu(NO3)2,  and  what  volume  of  nitric  oxide 
at  +  30°  C.  and  900  mm.  ? 

157.  As203  +  2HN03  +  2H20  =  2H3As04  +  ? 

If  100  g.  of  As2O3  are  used,  find  weight  and  volume  of 
gas  not  given  in  equation. 

158.  •  To  make  10  g.  of  nitrous  acid,  what  weights  of 
N2O3  and  H2O  are  needed? 

159.  If  37  1.  of  oxygen  are  mixed  with  39  1.  of  nitric 
oxide,  what  volume   of   a  new  gas   results  and  what 
volume  of  residue  is  left  ? 

160.  Lead  nitrate   on  being  heated  yields  30  1.  of 
oxygen.     Find  weight  of  lead  nitrate  heated. 


238     PROGRESSIVE  PROBLEMS   IN   CHEMISTRY 

161.  How  much  HNO3  would  100  Kg.  of  N2O5  make 
with  water? 

162.  Chili  saltpeter  treated  with  300  Kg.  of  H2SO4 
will  yield  what  weight  of  HNO3? 

163.  What  volume  of  chlorine  will  be  liberated  from 
100  g.  of  HC1  and  enough  HNO3  to  make  aqua  regia ; 
and  with  what  weight  of  gold  will  this  unite  ? 

164.  Given  300  g.  of  AuCl3,  what  weight  of  SnCl2 
will  be  required  to  precipitate  all  the  gold? 

165.  What  volume  of  HNO3  (sp.  gr.  1.42)  will  be 
needed  to  dissolve  31  g.  of  silver  and  what  volume  of 
gas  will  be  evolved? 

166.  KC1  and  NaNO3  are  allowed  to   act  on  each 
other  ;  300  Kg.  of  KNO3  result.     What  weights  of  the 
salts  were  used? 

167.  What  weight  of  H3PO3  will  yield  17  1.  of  PH3? 

168.  From  75  g.  of  P2O5  +  water,  what  weight  of 
orthophosphoric  acid  results? 

169.  A  mass  of  apatite  is  treated  with  100  tons  of 
H2SO4;  what  weight  of  CaH4(PO4)2  will  be  formed? 

170.  One  ton  of  Ca3(PO4)2  on  treatment  with  acid 
will  produce  what  weight  of  CaSO4  and  of  CaHPO4? 

171.  P4  +  3NaOH  +  3H20  =  3NaH2P02  +  PH3.   If 
300  g.  of  phosphorus  are  used,  what  are  the  weights  of 
the  other  members  of  the  above  equation,  and  what  is 
the  volume  of  the  gas  at  —  31°  C.  and  599  mm.? 

172.  H3 AsO4  is  made  from  As2O5  and  10  g.  of  water. 
Find  weight  of  materials  used  and  produced. 

173.  Na2S2O3  -f- 1  Kg.  HC1  =  what  weight  of  sulphur 
and  what  volume  of  SO9? 


PROBLEMS  BASED  ON  EQUATIONS    239 

174.  CuO  and  750  g.  of  H2SO4  produce  what  weights 
of  products? 

175.  One  g.  of  Na2CO3  and  1  g.   of  BaCl2  are  sepa- 
rately treated  with  H2SO4.     Find  weights  of  products. 

176.  PbS  is  roasted  with  oxygen.    If  a  ton  of  PbSO4 
is  produced,  what  volume  of  oxygen  has  been  used  at 
1  atmosphere  pressure  and  +  26°  C.  ? 

177.  Se  +  3  C12  +  4  H20  =  1  Kg.  of  H2SeO4  +  6  HC1. 
Find  weights  of  members  on  left  side  of  equation  and 
volume  of  HC1  produced. 

178.  2Cr(OH)2=21g.ofCr203  +  H20  +  H2.     Cal- 
culate the  weights  of  solids  in  equation  and  volume  of 
gas. 

179.  CrCl3  +  20  g.   of   caustic   soda  produce  what 
weight  of  salt  and  of  Cr(OH)3? 

180.  One  Kg.  of  Cr(OH)3  =  what  weight  of  CrO,  OH 
and  of  H20  ? 

181.  On  heating  100  g.  CrO3,  what  weight  of  Cr2O3 
do  you  get  and  how  many  m.3  of  O  ? 

182.  K2CrO4  is  decomposed  with  1  Kg.  of  H2SO4. 
Find  weight  of  K2CrO4  used  and  of  K2Cr2O7  produced. 

183.  K2Cr2O7  is  treated  with  30  g.  of  KOH  in  solu- 
tion.    Find  weight  of  material  used  and  produced. 

184.  Na2Cr2O7    is    changed   by   10   g.  of   KC1   into 
K2O2O7.     Find  weight  of  NaCl  produced. 

185.  On  heating  1  Kg.  of  K2Cr2O7,  what  weights  of 
normal  chromate,  Cr2O3,  and  volume  of  oxygen  do  you 
get? 

186.  Oil  of  vitriol  with  376  g.  of  K2Cr2O7  produces 
what  weights  of  materials  and  what  volume  of  gas  at 
-22°C.  and941mrn.? 


240     PROGRESSIVE  PROBLEMS  IN   CHEMISTRY 

187.  Cr2(SO4)3  +  23  g.  of  (NH4)2S  will  produce  what 
weight  of  Cr2S3  and  of  ammonium  sulphate  ? 

188.  Cr2S3,  on  treatment  with  99  cc.  of  H2O  at  0°  C. 
and  760  mm.,  yields  what  weight  of  substances? 

189.  Sugar  of  lead  +  10  g.  of  K2Cr2O7  =  how  much 
precipitate  ?     A  lead  salt  +  32  g.  of  K2CrO4  produces 
what  weight  of  lead  chromate  ? 

190.  One  Kg.  of  corrosive  sublimate  is  made  from 
what  weights  of  HgO  and  chlorine? 

191.  To  make  30  g.  of  HOC1,  how  much  C12O  and 
H2O  must  be  used  ? 

192.  C12  +  H2O  =  HC1  +  HOC1.    If  21 1.  of  chlorine 
at  +  8°  C.  and  600  mm.  are  used,  find  volume  of  HC1 
produced  at  standard  conditions. 

193.  HgO,  water,  and  333  1.  of  chlorine  are  placed  in 
a  vessel.     How  many  g.  of  HgCl2  and  of  HOC1  were 
produced  ? 

194.  Through  a  KOH   solution   is  passed   13  1.  of 
chlorine.     Find  the  weight  of  KOC1  made. 

195.  If  3  tons  of  slaked  lime  are  treated  with  chlorine, 
what  is  the  weight  of  bleaching  powder  produced? 

196.  Given  25  g.  of  HOC1,  what  volumes  of  HC1  and 
of  O  are  produced  when  it  is  exposed  to  sunlight  ? 

197.  HOC1+  3  g.  of  HC1  give  what  weight  of  chlo- 
rine and  of  water? 

198.  CaCl(OCl)  4-  8  g.  of  H2SO4  =  what  weight  of 
CaSO4  and  of  HOC1? 

199.  2  CaCl(OCl)  +  H2O  +  CO2  =  CaCO3  +  CaCl2-h 
2  HOC1.     If  13 1.  of  CO2  are  used,  find  weight  in  g.  of 
resulting  substances. 


PROBLEMS  BASED  ON  EQUATIONS    241 

200.  When  13  g.  of  NH3  react  on  NaBrO,  what  vol- 
ume of  nitrogen  is  given  off? 

201.  3  NaBrO  +  100  g.  CO(NH2)2  =  what  weight  of 
NaBr,  H2O,  N,  and  CO2  ? 

202.  3  HOC1  =  HOC1O2  +  2  HC1.      If  41  1.  of  HC1 
are  produced,  what  is  the  weight  of  HOC1  used? 

203.  Should  30  g.  of  KOC1  break  up,  find  weight  of 
KOC1O2  and  of  KC1  produced. 

204.  In  the  making  of  KC1O3,  100  1.  of  chlorine  were 
passed  through  a  solution  containing  300  g.  of  KOH. 
Find  the  weight  of  KC1O3  made  and  of  the  substance  in 
excess. 

205.  Ca(ClO3)2  +  100  g.  of  KC1  =  what  weight  of 
CaCl2  and  of  KC1O8? 

206.  One  Kg.  of  barium  chlorate  is  treated  with  H2SO4 
in  excess.     Find  weight  of  precipitate  and  of  HC1Q3. 

207.  HC1O3  +  5  g.  of  HC1  =  what  weight  of  H2O 
and  of  chlorine  ? 

203.    To  make  100  g.  of  HC1O3,  what  weights  of  C12O5 
and  of  water  are  needed? 

209.  C12O4  +  30  g.  H2O  =  how  many  g.  of  HC1O3  and 
ofHC102? 

210.  We  need  80  g.  of  HC1O2.     How  much  C12O3 
must  be  dissolved  in  water  to  produce  it  ? 

211.  Should  one  need  to  make  30  g.  of  HIO3,  what 
weight  of  I2O5  and  of  H2O  are  needed  ? 

212.  2HI03+5S02  +  4H20  =  5H2S04  +  I2.      To 
produce  30  g.  of  iodine  what  volume  of  SO2  at  —  9°  C. 
and  861  mm.  should  be  used  ? 

213.  2  HC1O3=HC1O2  +  HC1O4.     Should  20  g.  of 
HC1O3  be  used,  what  weight  of  HC102  will  result  ? 


242     PROGRESSIVE   PROBLEMS  IN   CHEMISTRY 

214.  Ba(ClO4)2  + 10  cc.  of  H2SO4  (sp.  gr.  =  1.84) 
will  produce  what  weight  of  residue  and  of  HC1O4  ? 

215.  If  77  g.  of  KC1O3  are  heated  just   to   fusion, 
what  weights  of  KC1O4,  KC1,  and  O  will  result  ? 

216.  1  g.  HC1O4  on  treatment  with  iodine  yields  how 
manyg.  of  HIO4andCl? 

217.  To  make  39  g.   of  Mn(OH)2   what   weight  of 
MnCl2  must  be  taken  and   how  many   cc.  of   a  40  % 
NaOH  solution  will  be  needed  ? 

218.  Mn2(SO4)3  +  90  cc.  of  NaOH  (25  %  solution) 
•will  yield  how  many  g.  of  Mn(OH)3  and  of  Na2SO4? 

219.  To  produce  21  1.  of  oxygen,  what  weights  of 
KMnO4  and  of  H2SO4  are  required  ? 

220.  2  KMnO4  +  10  FeSO4  +  8  H2SO4 

=  K2SO4  +  2  MnSO4  +  ?  +  ? 

Should   800   g.    of   KMnO4  be   used,  find  weights  of 
missing  terms  in  the  above  equation. 

221.  To   make   31   g.    of   H2SO4   what   weights    of 
KMnO4,  SO2,  and  H2O  are  required  ? 

222.  2  KMn04  +  5  H2O2  +  3  H2SO4 

==?+?  +  8H20  +  5O2. 

If  13  g.  of  H2O2  are  used,  what  weights   of  missing 
members  of  equation  and  1.  of  oxygen  are  produced  ? 

223.  2  KMnO4  +  5  C2H2O4  +  3  H2SO4 

=  ?  +  ?  +  10  CO2  +  8  H2O. 

If  20  g.  of  CO2  are  produced,  calculate  the  weight  of 
KMnO4  used  and  of  missing  factors  in  equation. 

224.  10  g.  manganese  chloride  with  (NH4)2S  yields 
how  many  g.  of  NH4C1  and  of  MnS  ? 

225.  Ferric  sulphate  with  300  g.  of  caustic  soda  in 
solution  produces  what  mass  of  ferric  hydroxide  ? 


PROBLEMS  BASED  ON   EQUATIONS          243 

226.  From  80  g.  of  ferrous  sulphate  +  (NH4)2S  what 
mass  of  FeS  will  result  ? 

227.  To  make  3  tons  of  CaC2  what  weights  of  lime 
and  C  are  needed? 

228.  A   million   m.3   of    C2H2    are    required.     How 
many  Kg.  of  materials  will  be  used  and  what  weight 
of  residue  will  be  left? 

229.  BN  +  3  H2O  =  B(OH)3  +  NH3.       To    produce 
80  cc.  of  NH3  what  weight  of  BN  must  be  taken  ? 

230.  NaNH2  +  31  cc.  of  H2O  will  give  what  weight 
of  NaOH  and  what  volume  in  1.  of  NH3  at  +  31°  C. 
and  800  mm.  pressure? 

231.  Mercuric  cyanide  on  being  heated   breaks   up 
into  3  g.  of  Hg  and  (CN)2  ;  what  weight  was  heated  ? 

232.  Potassium  cyanide  on  treatment  with  2  g.  H2SO4 
gives  what  volume  of  HCN  at  + 17°  C.  and  770  mm.  ? 

233.  From  2  Kg.  of  CaCN2  +  H2O  how  many  g.  of 
Ca(OH)2andof  H2CN2? 

234.  K4Fe(CN)6  is  reduced  with  30  g.  of  K.     What 
weight  of  Fe  and  of  KCN  are  left  ? 

235.  Litharge  +  1  g.  of  KCN  =  what  weight  of  Pb 
and  of  KCNO  ? 

236.  KCN  and  3  g.  of  AgNO3  will  give  what  mass  of 
saltpeter  and  of  AgCN? 

237.  3  K4Fe(CN)6  +  4  FeCl3  =  Prussian   blue    +  12 
KC1.     Should  8  g.  of  FeCl3  be  used,  find  the  weight 
of  Prussian  blue  produced. 

238.  2  K3Fe(CN)6  +  3  FeSO4  =  3  K2SO4  +  Turnbull's 
blue.     What    weight  of  Turnbull's  blue  can  be  made 
from  81  g.  of  FeSO4  ? 


APPENDIX 


I.  — INTERNATIONAL   ATOMIC   WEIGHTS,  1911 


Aluminium 
Antimony 

Symbol 
.     .     .     .  Al 
Sb 

Atomic 
Weight 
27.1 
120.2 

Molybdenum   .     .     . 
Neody  mi  um 

Symbol 
.  Mo 
.  Nd 

Atomic 
Weight 
96.0 
144  3 

Argon 

A. 

39  88 

Neon  ...              . 

Ne 

20  2 

Arsenic 

As 

74  96 

Nickel 

Ni 

58  68 

Ba 

137  37 

N 

14  01 

Bismuth 

.     .    .    .  Bi 

208.0 

Osmium  

.  Os 

190.9 

Boron 

...       B 

11.0 

Oxvsren 

.  O 

16  00 

Bromine 

Br 

79  92 

Palladium   . 

Pd 

106  7 

Cadmium    . 

.     .     .     .  Cd 

112.40 

Phosphorus 

.  p 

31.04 

Cs 

132  81 

Pt 

195  2 

Calcium  . 

.    .    .    .  Ca 

40.09 

Potassium   .     .     .     . 

.  K 

39.10 

Carbon 

.    .           C 

12  0 

Praseodymium 

.  Pr 

140  6 

Ce 

140  25 

Radium 

Ra 

226  4 

Cl 

35  46 

Rh 

102  9 

Chromium 

.     .     .  Cr 

52.0 

Rubidium    . 

.  Rb 

85.45 

Cobalt 

.  Co 

58.97 

Ruthenium 

Ru 

101  7 

Columbium  . 

.     .     .     .  Cb 

93.5 

Samarium  .... 

.  Sa 

150.4 

Copper 

.     .     .     .  Cu 

63.57 

Scandium    .     .     .     . 

.  Sc 

44.1 

Dysprosium 

.  Dy 

162.5 

Selenium     .... 

.  Se 

79.2 

Erbium 

.     .     .     .  Er 

167.4 

Silicon    

.  Si 

28.3 

Europium 

.  Eu 

152.0 

Silver 

As 

107  88 

Fluorine  .    . 

.     .     .     .  F 

19.0 

Sodium   

.  Na 

23.00 

Gadolinium 

.     .    .     .  Gd 

157.3 

Strontium    . 

.  Sr 

87.63 

Gallium  . 

.     .     .     .  Ga 

69.9 

Sulphur 

.  S 

32.07 

Germanium 

...       Ge 

72  5 

Ta 

181  0 

Glucinum 

Gl 

9  1 

Tellurium 

Te 

127  5 

Gold 

Au 

197  2 

Terbium 

Tb 

159  2 

Helium    . 

....  He 

3  99 

Thallium 

.  Tl 

204.0 

Hydrogen 

.    .            H 

1  008 

Th 

232  4 

Indium    . 

In 

114  8 

Thulium 

Tm 

168  5 

Iodine 

I 

126  92 

Tin 

Sn 

119  0 

Iridium   . 

.     .     .     .  Ir 

193.1 

Titanium     .... 

.  Ti 

48.1 

Iron    .    .    . 

.    .    .    .  Fe 

55  85 

Tungsten 

.  W 

184.0 

Krypton 

...       Kr 

82  92 

.  U 

238.5 

Lanthan  um 

.     .     .       La 

1390 

Vanadium  .... 

.  V 

51.06 

Lead 

.     .            Pb 

207  10 

.  Xe 

130.2 

Lithium 

Li 

6  94 

Lu 

1740 

(Neo-ytterbium) 

.  Yb 

1720 

Magnesium  . 

.  Mg 

24.32 

Yttrium  

.  Yt 

89.0 

Manganese  • 

.     .     .    .  Mn 

54.93 

Zinc    

.  Zn 

65.37 

Mercury  . 

.  Hff 

200.0 

Zirconium  . 

.  Zr 

90.6 

245 


246 


APPENDIX 


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APPENDIX 


247 


III.— THE  METRIC   SYSTEM 

The  fundamental  unit  of  the  metric  system  is  the  Meter  (the  unit  of 
length).  From  this  the  units  of  mass  (Gram)  and  capacity  (Liter)  are 
derived.  All  other  units  are  the  decimal  subdivisions  or  multiples  of 
these.  These  three  units  are  simply  related,  so  that  for  all  practical 
purposes  the  volume  of  one  kilogram  of  water  (one  liter)  is  equal  to 
one  cubic  decimeter. 


PREFIXES 

MEANING 

UNITS 

Milli- 

=  one  thousandth 

T^OlT 

.001 

Centi- 

=  one  hundredth 

TtfTF 

.01 

Deci- 

=  one  tenth 

A 

.1 

Meter  for  length 

unit 

=  one 

1. 

Gram  for  mass 

Deka- 

=  ten 

¥ 

10. 

Liter  for  capacity 

Hecto- 

=  one  hundred 

10.Q 

100. 

Kilo- 

=  one  thousand 

ioT<m 

1000. 

The  metric  terms  are  formed  by  combining  the  words  "Meter," 
Liter  "  with  the  six  numerical  prefixes. 

Length 

10  milli-meters  mm.  =  1  centi-meter 


10  centi-meters 
10  deci-meters 
10  meters 
10  deka-meters 
10  hecto-meters 


=  1  deci-meter 

=  1  Meter  (about  40  inches) 

=  1  deka-meter 

=  1  hecto-meter 

=  1  kilo-meter  (about  f-  mile) 


;  Gram,"  and 


em. 

dm. 

m. 

dkm. 
hm. 
km. 


Mass 

mg.  =  1  centi-gram  eg. 

=  1  deci-gram  dg. 

=  1  Gram  (about  15  grains)  g. 

=  1  deka-gram  dkg. 

=  1  hecto-gram  hg. 

=  1  kilo-gram  (about  2  pounds)  kg. 

Capacity 

=  1  centi-liter  cl. 

=  1  deci-liter  dl. 

=  1  Liter  (about  1  quart)  1. 

=  1  deka-liter  dkl. 

=  1  hecto-liter  (about  a  barrel)  hi. 

=  1  kilo-liter  kl. 
The  square  and  cubic  units  are  the  squares  and  cubes  of  the  linear  units. 
The  ordinary  unit  of  land  area  is  the  "  Hectare  "  (about  2£  acres). 


10  milli-grams 
10  centi-grams 
10  deci-grams 
10  grams 
10  deka-grams 
10  hecto-gram  s 

10  milli-liters 
10  centi-liters 
10  deci-liters 
10  liters 
10  deka-liters 
10  hecto-liters 


ml. 


248 


APPENDIX 


EQUIVALENTS 
1  Meter  =  39.37  Inches 

Legal  equivalent  adopted  by  Act  of  Congress,  July  28,  1866 

Length 


Centimeter 

=    0.3937 

inch 

Meter 

=    3.28 

feet 

Meter 

=    1.094 

yards 

Kilometer 

=    0.621 

statute  mile 

Kilometer 

=    0.5396 

nautical  mile 

Inch 

=    2.540 

centimeters 

Foot 

=    0.305 

meter 

Yard 

=    0.914 

meter 

Statute  mile 

=    1.61 

kilometers 

Nautical  mile 

=    1.853 

kilometers 

Area 


Sq.  centimeter 
Sq.  meter 
Sq.  meter 
Hectare 
Sq.  kilometer 

Sq.  inch 
Sq.  foot 
Sq.  yard 
Acre 
Sq.  mile 


0.155  sq.  inch 

10.76  sq.  feet 

1.196  sq.  yards 

2.47  acres 

0.386  sq.  mile 

6.45  sq.  centimeters 

0.0929  sq.  meter 

0.836  sq.  meter 

0.405  hectare 

2.59  sq.  kilometers 


Volume 

Cu.  centimeter  =  0.0610  cu.  inch 
Cu.  meter  =  35.3  cu.  feet 
Cu.  meter  =  1.308  cu.  yards 

Cu.  inch  =  16.39      cu.  centimeter 

Cu.  foot  =    0.0283  cu.  meter 

Cu.  yard  =    0.765    cu.  meter 


APPENDIX 


249 


EQUIVALENTS  —Continued 
Capacity 


Milliliter 

=    0.0338    U.  S.  liq.  ounce 

Milliliter 

=    0.2705    U.  S.  apoth.  dram 

Liter 

=    1.057      U.  S.  liq.  quarts 

Liter 

=    0.2642    U.  S.  liq.  gallon 

Liter 

.=    0.908      U.  S.  dry  quart 

Dekaliter 

=    1.135      U.  S.  pecks 

Hectoliter 

=    2.838      U.  S.  bushels 

U.  S.  liq.  ounce 

=  29.57        milliliters 

U.  S.  apoth.  dram 

=    3.70       milliliters 

U.  S.  liq.  quart 

=    0.946      liter 

U.  S.  dry  quart 

=    1.101      liters 

U.  S.  liq.  gallon 

=    3.785      liters 

U.  S.  peck 

=    0.881      dekaliter 

U.  S.  bushel 

=    0.3524    hectoliter 

Weight 

Gram 

=  15.43        grains 

Gram 

=    0.772      U.  S.  apoth.  scruple 

Gram 

=    0.2572    U.  S.  apoth.  dram 

Gram 

=    0.0353    avoir,  ounce 

Gram 

=    0.03215  troy  ounce 

Kilogram 

=    2.205      avoir,  pounds 

Kilogram 

=    2.679      troy  pounds 

Metric  ton 

=    0.984      gross  or  long  ton 

Metric  ton 

=    1.102      short  or  net  tons 

Grain 

=    0.0648    gram 

U.  S.  apoth.  scruple 

=    1.296      grams 

U.  S.  apoth.  dram 

=    3.89        grams 

Avoir,  ounce 

=  28.35        grams 

Troy  ounce 

=  31.10       grams 

Avoir,  pound 

=    0.4536    kilogram 

Troy  pound 

=    0.373     kilogram 

Gross  or  long  ton 

=    1.016      metric  tons 

Short  or  net  ton 

=    0.907      metric  ton 

250 


APPENDIX 


Area  of  triangle 
Area  of  triangle 


Mensuration  Rules 

=  \  (base  x  altitude). 


Area  of  parallelogram 
Area  of  trapezoid 
Circumference  of  circle 

Diameter  of  circle 

Area  of  circle 

Area  of  ellipse 
Area  of  regular  polygon 
Lateral  surface  of  cylinder 
Volume  of  cylinder 

Surface  of  sphere 

Volume  of  sphere 

Surface  of  pyramid  \ 
Surface  of  cone  J 
Volume  of  cone 


=  Vs  (s  —  a)  (s  —  6)  (s  — -  c) ,  where 

s=  i(«  +  &  +  C). 
=  base  x  altitude. 

=  altitude  x  |  sum  of  parallel  sides. 
=  diameter  x  3.1416. 
_  (  circumference  -=-3.1416. 
~  I  circumference  x  0.3183. 

( diameter  squared  x  0.7854. 
~  I  radius  squared  x  3.1416. 
=  product  of  diameters  x  0.7854. 
=  £  (sum  of  sides  x  apothem). 

circumference  of  base  x  altitude. 

area  of  base  x  altitude. 

f  diameter  x  circumference. 

\4  x  3.1416  x  square  of  radius. 

f  diameter  cubed  x  0.5236. 

A  |  of  radius  cubed  x  3.1416. 

I  (circumference  of  base  x  slant 

height) . 

\  (area  of  base  x  altitude) . 


APPENDIX 


251 


IV.  — SPECIFIC   GRAVITY  OF   GASES* 


Name 

Formula 

Molecu- 
lar 
Weight 

Specific  Gravity, 
Air  =  1 

Weight  in 
Grams  of  1 
Liter  at  0°, 
760  mm.  at 
Sea  Level, 
lat.  45°. 

Calcu- 
lated 

Observed 

Acetylene   .... 
Air     
Ammonia    .... 

C2H2 

NH3 
A 
AsH3 
Br2 
C4H10 
C02 
CO 
COS 
C12 
C2N2 
C2H6 
C2H4 
F2 
He 
HBr 
HC1 
HF 
HI 
H2 
H2Se 
H2S 
H2Te 
Kr 
CH4 
Ne 
NO 
N20 
N2 
N2+A  etc. 
N02 
N204 
NOC1 
02 
PH3 
C3H6 
SiF4 
S02 
X 

26.016 

17.064 
39.9 
78.024 
159.92 
58.08 
44.00 
28.00 
60.06 
70.90 
52.08 
30.048 
28.032 
38.0 
4 
80.968 
36.458 
20.008 
127.98 
2.016 
81.216 
34.076 
129.62 
81.8 
16.032 
20 
30.04 
44.08 
28.08 

46.04 
92.08 
65.49 
32.00 
34.024 
42.048 
104.4 
64.06 
128 

0.8988 
1.0000 
0.5895 
1.379 
2.696 
5.5249 
2.0065 
1.5201 
0.9673 
2.0749 
2.489 
1.7993 
1.0381 
0.9784 
1.313 
0.1382 
2.7973 
1.2595 
0.691 
4.4172 
0.06965 
2.806 
1.1773 
4.478 
2.826 
0.5539 
0.691 
1.0378 
1.5229 
0.9701 

1.5906 
3.1812 
2.2625 
1.1055 
1.175 
1.4527 
3.607 
2.2131 
4.422 

0.92 

0.5971 
1.379 
2.695 
5.524(227.9°) 
2.01 
1.52909 
0.96716 
2.1046 
2.491 
1.8064 
1.075 
0.9852 
1.26 
0.1368 
2.71 
1.2692 
0.7126 
4.3757 
0.06960 
2.795 
1.1895 
4.489 
2.818 
0.5576 
0.674 
1.0367 
1.5301 
0.96737 
0.97209 
1.60  (135°) 
2.65  (26.7°) 
2.31 
1.10535 
1.214 
1.498 
3.60 
2.2639 
4.422 

1.1620 
1.29330 
0.7621 
1.7828 
3.485 
7.1426 
2.594 
1.9652 
1.2506 
2.6825 
3.1666 
2.3261 
1.3421 
1.2520 
1.697 
0.1787 
3.6163 
1.6283 
0.894 
5.7106 
0.089873 
3.627 
1.5230 
5.789 
3.654 
0.7160 
0.893 
1.3402 
1.9688 
1.2542 
1  .25718 
2.0563 
4.1126 
2.925 
1.4290 
1.520 
1.8780 
4.663 
2.8611 
5.717 

Arsine    

Bromine      .... 

Carbon  dioxide    .     . 
Carbon  monoxide    . 
Carbon  oxysulphide 
Chlorine      .... 
Cyanogen    .... 
Ethane   .     .          . 

Ethylene     .... 
Fluorine      .... 
Helium   

Hydrobromic  acid   . 
Hydrochloric  acid   . 
Hydrofluoric  acid    . 
Hydroiodic  acid  .     . 
Hydrogen   .... 
Hydrogen  selenide  . 
Hydrogen  sulphide  . 
Hydrogen  telluride  . 
Krypton      .... 
Methane      .... 
Neon  

Nitric  oxide    .     .     . 
Nitrous  oxide  .     .     . 
Nitrogen     .... 
atmospheric     .     . 
Nitrogen  dioxide 
Nitrogen  dioxide 
Nitrosyl  chloride 
Oxvfiren 

Phosphine  .... 
Propylene   .... 
Silicon  fluoride    .     . 
Sulphur  dioxide  .     . 
Xenon     .    . 

*  Quoted  from  Landolt-Bornstein.  Phys.-Chem.  Tabellen,   1905,  p. 
with  revisions  by  Olsen. 


222, 


252 


APPENDIX 

V.  — PHYSICAL  CONSTANTS 


[  Number  j  ] 

Name 

Sym- 
bol 

Atomic 
Weight 
O  =  16 

Molec- 
ular 
Weight 

Specific 
Gravity 
Water  =1 
Air=l  (A) 
Hydrogen  = 
1  (D) 

\tomic 
Vol. 
At.Wt. 

Specific 
Heat 
at  0°  C. 

8p.  Gr. 

1 

Aluminium     .     . 

Al 

27.1 

2.5834° 

10.5 

.2220 

2 

Antimony  .     .     . 

Sb 

120.2 

6.62 

18.2 

.0495 

8 

Argon,  gas      .     . 

A 

39.9 

39.9 

(1.379  A 
I  19.96  D 

.1233 

4 

liquid  .... 

A 

39.9 

1.4046-1860 

28.5 

5 

Arsenic,  amorph. 

As 

75.0 

300 

4.716140 

15.9 

.0758  {  21°- 

6 

cryst  

As 

75.0 

300 

5.727140 

13.2 

.0830  I  65° 

7 

Barium  .... 

Ba 

137.4 

3.75 

36.7 

8 

Bismuth      .     .     . 

Bi 

208.5 

9.7474 

21.4 

.03013 

9 

Boron,  amorph.  . 

B 

11.0 

2.45 

4.5 

.3066 

10 

cryst  

B 

11.0 

2.53-2.68 

4.2 

11 

Bromine,  gas  .     . 

Br2 

79.96 

159.92 

5.869160°  A 

.0555(83°) 

12 

liquid.     .     .     . 

Br2 

79.96 

159.92 

3.18830° 

25 

.1071 

13 

Cadmium   .     .     . 

Cd 

112.4 

112.4 

8.64217° 

13 

.0548 

14 

Caesium  .... 

Cs 

132.9 

2.366 

56 

.04817 

in 

CalSium      .    .    . 

Ca 

40.1 

1.544629.20 

26 

.1804 

1(5 

Carbon,  amorph. 

C 

12.00 

1.75-2.10 

6.0 

.241 

17 

graphite  .     .    . 

C 

12.00 

2.10-2.585 

5 

.202 

IS 

diamond  .     .     . 

C 

12.00 

3.47-3.5585 

3.4 

.1469 

19 

Cerium  .... 

Ce 

140.25 

7.0424 

20 

.04479 

20 

Chlorine,  gas  .     . 

Cl 

35.45 

70.90 

2.491°°A 

.1241 

21 

liquid  .... 

Cl 

35.45 

1.44050° 

24.6 

.2262 

22 

Chromium  .     .     . 

Cr 

52.1 

6.9220 

7.6 

.10394 

23 

Cohalt    .    [bium) 

Co 

59.0 

8.718H0 

6.8 

.1030 

24 

Columbium  (Nio- 

Cb 

94.0 

7.06i|° 

13.3 

25 

Copper  .... 

Cu 

63.6 

8.91-8.96 

7.1 

.0936 

21  i 

Erbium  .... 

Er 

166 

4.77 

34.8 

27 

Fluorine,  gas  .     . 

F 

19 

38 

1.31i5°A 

28 

liquid  .... 

F 

19 

38 

1.14-1870 

16.7 

2<> 

Gadolinium     .     . 

Gd 

156 

1.31 

119.1 

;io 

Gallium      .     .    . 

Ga 

70 

5.9524° 

11.8 

.079 

31 

Germanium     .     . 

Ge 

72.5 

5.469|§ 

13.3 

.0737 

:52 

Glucinum  (Beryl- 

Gl 

9.1 

1.8520°A 

4.9 

x; 

Gold    .     .     [Hum) 

Au 

197.2 

19.32 

10.2 

.0316 

;u 

Helium,  gas    .    . 

He 

4 

4 

C  0.1368  A 
1  1.98  D 

*From  Van  Nost rand's  Chemical  Annual — Olsen. 
f  K  =  the  number  of  grams  of  water  which  can  be  raised  from  0°  to  1°  C. 
by  the  heat  which  passes  through  a  cubic  centimeter  of  the  substance  in 


APPENDIX 


253 


OF   THE   ELEMENTS* 


Number 

||? 

Electrical 
Conduc- 
tivity 
at  0°  C. 

Thermal 
Conduc- 
tivity 
Kt  at  0°  C. 
Ag-  =  1.00 

Linear 
Coefficient  of 
Expansion 

Melting 
Point, 

Boiling 
Point, 

1 

6.02 

324000 

.3435 

.042313 

At°C. 
40° 

657° 

1470-1700° 

2 

5.95 

27100 

.0442 

.041152 

40° 

630° 

1500-1700° 

3 

4.92 

.043894 

—187.9° 

-  186.1° 

4 

6 

5.69 

28600 

.040559 

40° 

<360° 

6 

6.23 

sublimes  at 

449*° 

7 

850° 

vol.  950° 

8 

6.28 

9260 

.0177 

.041346 

40° 

269° 

1435° 

1) 

3.37 

infusible 

sublimes  at 

10 

infusible 

3500° 

11 

4.44 

12 

8.57 

-7.3° 

59° 

13 

6.16 

146000 

.2213 

.043069 

40° 

321.7° 

778° 

14 

6.41 

25400 

.0339482 

27-100° 

26.37° 

670° 

15 

7.23 

95000 

780-810° 

16 

2.89 

.04054 

40° 

sublimes 

3500° 

17 

2.22 

.040786 

40° 

sublimes 

3500° 

18 

1.76 

.040118 

40° 

sublimes 

3500° 

19 

6.28 

623° 

20 

4.40 

-102° 

-  33.6° 

21 

8.02 

•021978 

0-10° 

22 

5.42 

1515° 

23 

6.08 

83200 

.041236 

40° 

1530° 

24 

1950° 

25 

5.95 

640600 

.7198 

.041678 

40°      { 

1084° 
1065°(inair) 

2100° 

27 

—  223° 

—  187° 

28 

—  223° 

—  187° 

29 

30 

5.53 

30.15° 

31 

5.34 

900° 

vol.  1350° 

32 

>960° 

33 

6.23 

468000 

.7003 

.041470 

0-100° 

1065° 

34 

.033386 

<  -  271.3° 

-267° 

one  second  when  the  temperatures  of  the  opposite  sides  of  the  cube  are 
maintained  at  a  difference  of  1°  C. 


254 


APPENDIX 


Number  || 

Name 

Sym- 
bol 

Atomic 
Weight 
O  =  16 

Molec- 
ular 
Weight 

Specific 
Gravity 
Water=l 
Air=l  (A) 
Hydrogen  = 
1(D) 

Atomic 
Vol. 
At.Wt. 

Specific 
Heat 
at  0°  C. 

Sp.  Gr. 

1 

Hydrogen,  gas     . 

H 

1.008 

2.016 

0.06949  A 

3.410 

2 

liquid  .... 

H 

1.008 

2.016 

0.700-252.60 

1.4 

6. 

3 

Indium  .... 

In 

115 

7.12?- 

16.1 

.05695 

4 

Iodine,  gas  .     .     . 

I 

126.97 

8.72  A 

.0336206° 

K 

solid    ..... 

I 

126.97 

253.94 

4.94817° 

25.7 

.05412 

6 

Iridium,  spongy  . 

Ir 

193.0 

15.86 

12.2 

7 

crystalline    .     . 

Ir 

193.0 

22.42 

8.6 

.0323 

8 

Iron,  pure  .          . 

Fe 

55.9 

7.85-7.88 

7.1 

.1162 

a 

wrought  .     .     . 

Fe 

55.9 

7.86 

7.1 

.1130 

10 

steel    .... 

Fe 

55.9 

7.60-7.80 

7.3 

.1066 

11 

gray  pig  .     .     . 

Fe 

55.9 

7.03-7.13 

7.9 

12 

white  pig     .     . 

Fe 

55.9 

7.58-7.73 

7.3 

.1050 

13 

Krypton,  gas  .     . 

Kr 

81.8 

81.8 

(  2.818  A 
I  40.78  D 

14 

liquid  .... 

Kr 

81.8 

2.155-152° 

37.9 

15 

Lanthanum     .     . 

La 

138.9 

6.1545 

22.6 

.04485 

K; 

Lead  

Pb 

206.9 

11.34 

18.2 

.0310 

17 

Lithium.     .     .     . 

Li 

7.03 

0.5936 

12 

.9408 

IS 

Magnesium     .     . 

Mg 

24.36 

1.69-1.75 

14.3 

.2456 

1!) 

Manganese      .     . 

Mn 

55.0 

7.42 

7.4 

.1217 

20 

Mercury      .     .     . 

Hg 

200.0 

200.00 

13.59532 

14.7 

.03346 

21 

Molybdenum  .     . 

Mo 

96.0 

8.6-9.01 

10.9 

.0659 

22 

Neodymium    .     . 

Nd 

143.6 

6.9563 

20.6 

i:\ 

Neon  

Ne 

20 

|  0.674  A 

1  9.96  D 

24 

Nickel    .... 

Ni 

58.7 

8.6-8.93 

6.7 

.1084 

25 

Nitrogen,  gas  .     . 

N 

14.04 

28.08 

0.96737  A 

.2438 

2<; 

liquid  .... 

N 

14.04 

0.8042-195.50 

17.5 

27 

Osmium      .     .     . 

Os 

191 

22.48 

8.5 

.03113 

28 

Oxygen,  gas    .     . 

0 

16 

32 

1.10535  A 

.2175 

29 

liquid  .... 

0 

16 

32 

1.1181-182.5° 

14.3 

30 

Ozone     .... 

03 

48 

1.658  A 

31 

Palladium  .    .    . 

Pd 

106.5 

11.4-11.9 

9.2 

.0592 

32 

Phosphorus,   yel. 

P 

31 

124 

1.823220° 

17.2 

.202 

33 

red  

P 

31 

124 

2.11 

14.7 

.16981 

34 

liquid  .... 

P 

31 

1.76444.30 

35 

Platinum    .     .     . 

Pt 

194.8 

21.  481™* 

9.2 

.0323 

3<> 

Potassium  .     .     . 

K 

39.15 

0.87513° 

44.7 

.1662 

37 

Praseodymium    . 

Pr 

140.5 

6.4754 

21.6 

38 

Radium  .... 

Ra 

225 

39 

Rhodium    .     .     . 

Rh 

103.0 

12.1 

8.5 

.05803 

40 

Rubidium   .    .     . 

Rb 

85.5 

1.52215° 

56.3 

APPENDIX 


255 


|  Number  II 

11* 

Effi~ 

41-x 

Electrical 
Conduc- 
tivity 
at  0°"C.  ' 

Thermal 
Conduc- 
tivity 
Kt  at  0°  C. 
Ag  =  1.00 

Linear 
Coefficient  of 
Expansion 

Melting 
Point, 
°C. 

Boiling 
Point, 
°C. 

1 

3.44 

.033270 

At°C. 

—  256.5° 

-  252.5° 

2 

6.05 

o 

6.56 

119500 

.04417 

40° 

115° 

red  heat 

4 

4.27 

5 

6.86 

.04837 

-190-17 

114.2° 

184.35° 

6 

7 

6.23 

.040700 

40° 

1950° 

8 

6.50 

131000 

.1665 

.041182 

0°-100° 

1804° 

9 

6.32 

.2070 

.0411 

0°-100° 

1600° 

10 

5.96 

63000 

.1300 

.0411 

0°-100° 

1375° 

11 

{  10200- 

.041061 

40° 

1275° 

1L> 

5.87 

(11300 

.1490 

1075° 

13 

—  169° 

—  151.7° 

14 

15 

6.23 

810° 

1(5 

3.52 

504CO 

.0836 

.042924 

40° 

327° 

1400-1600° 

17 

6.62 

119000 

186° 

>1400° 

IS 

5.98 

230000 

.3760 

.042694 

40° 

632.6° 

1100° 

19 

6.70 

1245° 

20 

6.69 

10630 

.0148 

.03182 

0°-100° 

—  38.85° 

357.33° 

21 

6.33 

22 

840° 

23 

f  243°  to 

1  -  233° 

24 

6.36 

144200  i 

.1420 

.041279 

40° 

1484° 

25 

3.42 

.04524 

—  210.5°  (84 

-  195.5° 

2<; 

[mm.) 

27 

5.95 

105300 

.040657 

40° 

2500° 

28 

3.48 

.04563 

<  —  230° 

—  182.5° 

29 

30 

decomp.  270° 

-119° 

31 

6.30 

97900 

.1683 

.041176 

40° 

1535-1586° 

32 

6.26 

.03124 

0°-44° 

44.2° 

290° 

33 

5.26 

350°  (yel.) 

34 

35 

6.29 

91200 

.1664 

.040899 

40° 

1710-1780° 

36 

6.51 

150500 

.0483 

0°-50° 

62.5° 

757.5° 

37 

940° 

38 

39 

5.97 

.040850 

40° 

1650-2000° 

40 

38.5° 

696° 

f  See  note  on  p.  252. 


256 


APPENDIX 


|  Nnmber  1  1 

Name 

Sym- 
bol 

Atomic 
Weight 
0     16 

Molec- 
ular 

Weight 

Specific 
Gravity- 
Water  =  1 
Air  =  l  (A) 
Hydrogen  = 

Atomic 
Vol. 
At.Wt. 

Specific 
Heat 
at  0°  C. 

Sp.  Qr. 

1 

Ruthenium,  spon. 

Ru 

101.7 

8.6 

11.8 

2 

melted     .     .     . 

Ru 

101.7 

11.4 

8.9 

3 

cryst  

Ru 

101.7 

12.268° 

8.3 

.0611 

4 

Samarium  .    .    . 

Sm 

150.3 

7.7-7.8 

19.4 

5 

Scandium   .     .     . 

Sc 

44.1 

6 

Selenium,  amorph. 

Se 

79.2 

633.6 

4.26-4.2825° 

18.5 

.09533 

7 

monoclinic  .     . 

Se 

79.2 

633.6 

4.4725° 

17.7 

.08401 

8 

hexagonal    .     . 

Se 

79.2 

633.6 

4.825° 

16.5 

(.) 

Silicon,    amorph. 

Si 

28.4 

2.00 

14.2 

10 

cryst  

Si 

28.4 

2.49i°° 

11.4 

.169722° 

11 

Silver     .     .    .    . 

Ag 

107.93 

10.53 

10.2 

.0559 

12 

Sodium  .... 

Na 

23.05 

0.973513.50 

23.7 

.2934 

13 

Strontium  .    .    . 

Sr 

87.6 

2.54 

34.5 

Sulphur, 

14 

amorphous  soft 

S 

32.06 

256.48 

1.9556°° 

16.4 

15 

"      yellow 

S 

32.06 

256.48 

2.046 

15.6 

16 

rhombic  .     .     . 

Sa 

32.06 

256.48 

2.05-2.07°° 

15.6 

.163 

17 

monoclinic  .     . 

S/3 

32.06 

256.48 

1.958 

16.4 

18 

plastic     .     .     . 

Sy 

32.06 

256.48 

1.92 

16.7 

11) 

Tantalum  .     .     . 

Ta 

183 

12.79 

143 

20 

Tellurium,  amorp. 

Te 

127.6 

255.2 

6.0152°° 

21.2 

21 

cryst  

Te 

127.6 

255.2 

6.27 

20.4 

.0475 

22 

Terbium      .     .     . 

Tb 

160 

23 

Thallium    .     .     . 

Tl 

204.1 

11.85 

17.2 

.0326 

24 

Thorium,  amorph. 

Th 

232.5 

11.0011° 

21.1 

2f> 

cryst  

Th 

232.5 

11.23 

20.7 

20 

Thulium  .... 

Tm 

171 

27 

Tin,  gray     .     .     . 

Sn 

119.0 

5.846615° 

20.3 

.0545 

28 

rhombic  .     .     . 

Sn 

119.0 

6.53-6.56 

18.2 

.0559 

2!) 

tetragonal   .     . 

Sn 

119.0 

7.298415° 

16.3 

.0559 

30 

Titanium    .     .     . 

Ti 

48.1 

3.543 

13.6 

.1125 

31 

Tungsten    .     .     . 

W 

184 

18.77 

9.8 

.0336 

32 

Uranium     .     .     . 

u 

238.5 

18.685V30 

12.8 

.0280 

33 

Vanadium  .    .     . 

V 

51.2 

5.8715° 

8.7 

.1153 

34 

Xenon,  gas     .    . 

Xe 

128 

|  4.422  A 
1  63.5  D 

35 

liquid.     .     .     . 

Xe 

128 

3.52-109.10 

49.1 

36 

Ytterbium  .     .     . 

Yb 

173.0 

37 

Yttrium      .     .     . 

Yt 

89.0 

3.8015° 

23.4 

38 

Zinc   

Zn 

65.4 

7.14216° 

9.2 

.09356 

3!) 

Zirconium,  amorp. 

Zr 

90.6 

4.15 

21.8 

40 

cryst  

Zr 

90.6 

5.3 

17.1 

.0660 

APPENDIX 


257 


i  Number  1  1 

*j*  - 

Electrical 
Conduc- 
tivity 
at  0°  Wt. 

Thermal 
Conduc- 
tivity 
Kt  at  0°  C. 
Ag  =  1.00 

Linear 
Coefficient  of 
Expansion 

Melting 
Point, 

foiling 
Point, 

1 

At  °  C. 

>  1950° 

2 

2000° 

3 

6.21 

.040963 

40° 

2000° 

4 

5 

6 

7.55 

50° 

690° 

7 

6.65 

.043680 

40° 

170°-18° 

690° 

8 

217° 

690° 

g 

3500° 

10 

4.82 

200-15600 

.040763 

40° 

1200° 

3500° 

11 

6.04 

681200 

1.000 

.041921 

40° 

961.5° 

2050° 

12 

6.76 

211000 

.365 

.0472 

0°-50° 

97.6° 

877.5° 

1.3 

40300 

900° 

14 

>120° 

444.6° 

15 

444.6° 

1(5 

5.23 

.046413 

40° 

114.5° 

444.6° 

17 

119.25° 

444.6° 

18 

444.6° 

19 

60600 

.0408 

2250° 

20 

.041675 

40° 

446° 

1390° 

21 

6.07 

46600 

.043440 

0°-20° 

452° 

1390° 

22 

23 

6.65 

56800 

.043021 

40° 

301.7° 

1600-1800° 

24 

25 

27 

6.49 

stable  <20° 

28 

6.65 

stable  >170° 

29 

6.65 

76600 

.1528 

.042234 

40° 

232° 

1450-1600° 

30 

5.41 

3000° 

31 

6.18 

1700° 

32 

6.68 

800° 

33 

5.90 

1680° 

34 

-1403 

-  109.1° 

35 

37 

38 

6.12 

186000 

.2653 

.042918 

40° 

419° 

918° 

39 

1500° 

40 

5.98 

t  See  note  on  p.  252. 


258 


APPENDIX 


VI.  — VOLUME  AND  WEIGHT  OF  WATER  FROM  0°  C.  TO  31°  C.* 


Tempera- 
ture 

Volume  of  one 
gram  in  c.c. 

,  Weight  of  one 
c.c.  in  grams 

Tempera- 
ture 

Volume  of  one 
gram  in  c.c. 

Weight  of  one 
c.c.  in  grams 

0° 

1.000126 

0.999874 

16° 

1.001025 

0.998976 

1 

1.000070 

0.999930 

17 

1.001193 

0.998808 

2 

1.000030 

0.999970 

18 

1.001373 

0.998629 

3 

1.000007 

0.999993 

19 

1.001564 

0.998438 

4 

'  1.000000 

1.000000 

20 

1.001768 

0.998235 

5 

1.000008 

0.999992 

21 

1.001981 

0.998023 

6 

1.000031 

0.999969 

22 

1.002204 

0.997801 

7 

1.000069 

0.999931 

23 

1.002438 

0.997568 

8 

1.000122 

0.999878 

24 

1.006781 

0.997326 

9 

1.000188 

0.999812 

25 

1.002935 

0.997073 

10 

1.000269 

0.999731 

26 

1.003199 

0.996811 

11 

1.000363 

0.999637 

27 

1.003472 

0.996540 

12 

1.000470 

0.999530 

28 

1  003788 

0.996226 

13 

1.000590 

0.999410 

29 

1.004045 

0.995971 

14 

1.000722 

0.999278 

30 

1.004346 

0.995673 

15 

1.000867 

0.999134 

31 

1.004656 

0.995365 

For  the  most  recent  results  on  the  expansion  of  water, 
which  do  not  differ  materially  from  the  preceding,  see  An- 
nalen  d.  Physik  u.  Chemie,  [K  R],  60,  340  (1897). 
*  Wied.  Ann.,  47,  400  (1892). 


APPENDIX 


259 


VII.  — VAPOR  PRESSURE  OF  WATER  FROM  0°  C.  TO  100°  C. 
IN   MILLIMETERS   OF  MERCURY.* 


Temp. 

Pressure 

Temp. 

Pressure 

Temp. 

Pressure 

Temp. 

Pressure 

0 

4.569 

25 

23.517 

50 

91.98 

75 

288.76 

1 

4.909 

26 

24.956 

51 

96.66 

76 

301.09 

2 

5.272 

27 

26.471 

52 

101.55 

77 

313.85 

3 

5.658 

28 

28.065 

53 

106.65 

78 

327.05 

4 

6.069 

29 

29.744 

54 

111.97 

79 

340.73 

5 

6.507 

30 

31.51 

55 

117.52 

80 

354.87 

6 

6.972 

31 

33.37 

56 

123.29 

81 

369.51 

7 

7.466 

32 

35.32 

57 

129.31 

82 

384.64 

8 

7.991 

33 

37.37 

58 

135.58 

83 

400.29 

9 

8.548 

34 

39.52 

59 

142.10 

84 

416.47 

10 

9.140 

35 

41.78 

60 

148.88 

85 

433.19 

11 

9.767 

36 

44.16 

61 

155.95 

86 

450.47 

12 

10.432 

37 

46.65 

62 

163.29 

87 

468.32 

13 

11.137 

38 

49.26 

63 

170.02 

88 

486.76 

14 

11.884 

39 

52.00 

64 

178.86 

89 

505.81 

15 

12.674 

40 

54.87 

65 

187.10 

90 

525.47 

16 

13.510 

41 

57.87 

66 

195.67 

91 

545.77 

17 

14.395 

42 

61.02 

67 

204.56 

92 

566.71 

18 

15.330 

43 

64.31 

68 

213.79 

93 

588.83 

19 

16.319 

44 

67.76 

69 

223.37 

94 

610.64 

20 

17.363 

45 

71.36 

70 

233.31 

95 

633.66 

21 

18.466 

46 

75.13 

71 

243.62 

96 

657.40 

22 

19.630 

47 

79.07 

72 

254.30 

97 

681.88 

23 

20.858 

48 

83.19 

73 

265.38 

98 

707.13 

24 

22.152 

49 

87.49 

74 

276.87 

99 

733.16 

*  Taken  from  Ostwald's  Manual  of  Physico-Chemical  Measurements. 


260 


APPENDIX 


VIII. —TABLE  OF  ELECTRO-CHEMICAL  EQUIVALENTS 

Table  of  Electro-chemical  Equivalents  based  on  the  definition  of  the 
ampere  and  the  atomic  weights,  oxygen  being  16 


Element 

Atomic  Weight 

Valency 

Chemical 
Equivalent 

Electro-chemical 
Equivalent 
Grams  pef 
coulomb 

Coulombs 
per  gram 

(J  rains  per 
ampere-hour 

Ampere-hours 
per  pound 

Electropositive 

Aluniinum    .... 

27.11 

3. 

9.037 

.00009362 

10680. 

.3370 

1346. 

Antimony     .... 

120.43 

3. 

40.14 

.0004159 

2405. 

1.497 

303.0 

Bismuth  

208.11 

3. 

69.37 

.0007186 

1392. 

2.587 

175.3 

Cadmium     .... 

112.38 

2. 

56.19 

.0005821 

1718. 

2.096 

216.4 

Cobalt      

58.99 

2. 

29.5 

.0003056 

3272. 

1.100 

412.2 

Copper  (cuprous) 

63.6 

1. 

63.6 

.0006589 

1518. 

2.372 

191.2 

Copper  (cupric)     .     . 

63.6 

2. 

31.8 

.0003295 

3036. 

1.186 

382.4 

Gold     

197.23 

3. 

65.78 

.0006815 

1467. 

2.453 

184.7 

Hydrogen     .... 

1.008 

1. 

1.008 

.00001044 

95785. 

.03758 

12070. 

Iron  (ferrous)  .     .     . 

56.02 

2. 

28.01 

.0002902 

3446. 

1.045 

434.0 

Iron  (ferric)      .     .     . 

56.02 

3. 

18.67 

.0001934 

5171. 

.6962 

651.5 

Lead 

20fi  Q9 

2. 

103.5 

.001072 

932.8 

3.859 

117.5 

Magnesium  .... 

^UO.r/^ 

24.28 

2. 

12.14 

.0001258 

7949. 

.4528 

1001. 

Manganese  .... 

54.99 

2. 

27.50 

.0002849 

3510. 

1.026 

442.1 

Mercury  (mercurous) 

200. 

1. 

200. 

.002072 

482.6 

7.459 

60.81 

Mercury  (mercuric)  . 

200. 

2. 

100. 

.001036 

965.3 

3.730 

121.6 

Nickel      

58.69 

2. 

29.35 

.0003041 

3288. 

1.095 

414.2 

Platinum      .... 

194.89 

4. 

48.72 

.0005047 

1981. 

1.817 

249.6 

Potassium    .... 

39.11 

1. 

39.11 

.0004052 

2468. 

1.459 

310.9 

Silver 

107  <¥> 

1 

107.92 

.001118 

894.5 

4.025 

112.7 

Sodium     

i\j  ^  •  *?£ 
23.05 

1. 

23.05 

.0002388 

4188. 

.8597 

527.6 

Tin  (stannous)      .     . 

119.05 

2. 

59.52 

.0006166 

1622. 

2.220 

204.3 

Tin  (stannic)     .     .     . 

119.05 

4. 

29.76 

.0003083 

3243. 

1.110 

408.6 

Zinc          

65.41 

2. 

32.70 

AAAOOOO 

2952. 

1.220 

371.8 

Electronegative 

.  UUUOOOo 

Bromine  • 

79.95 

j€ 

79.95 

AAAQOQQ 

1207. 

2.982 

152.1 

Chlorine  

35.45 

1. 

35.45 

•vUUojJoO 

.0003673 

2723. 

1.322 

343.1 

Iodine  

126.85 

1, 

126.85 

.001314 

761.0 

4.730 

95.90 

Nitrogen  . 

14.04 

3. 

4.68 

.00004848 

20627. 

.1745 

2599. 

16. 

2. 

S. 

.00008288 

12066. 

.2984 

1520. 

APPENDIX 


261 


IX.— TABLE   SHOWING   THE   RELATIONS  BETWEEN  UNITS 
OF  ELECTRICITY,    HEAT,    AND   POWER 


1  ampere  =  1  volt  -r- 1  ohm. 

"        =1  coulomb  per  second. 

1  ampere  hour  =  1  coulomb  per  sec- 
ond kept  up  for 
one  hour. 

1  ampere  hour  =  3600  coulombs. 
1  volt  =  1  ampere  X  1  ohm. 
1  ohm  =  1  volt  -4- 1  ampere. 

1  joule  =  1  volt  x  1  coulomb. 
"       =  .2381  calorie. 

=  .73732  foot-pound. 
"       =  .10194  kilogram-meter. 

1  calorie  =  4.2  joules. 

=  3.0968  foot-pounds. 
"        =  .42815  kilogram-meter. 

1  foot-pound  =  1.3563  joules. 
=  .32292  calorie. 
=  .13825  kilogram- 
meter. 

1  kilogram-meter  =  9.81  joules. 

"  =2.3362  calories. 

=  7.233  foot- 
pounds. 

1  watt-hour  =  1  watt  kept  up  for 
one  hour. 

1  watt-hour  — •  1  joule  per  second 
kept  up  for  one 
hour. 

1  watt-hour  =  3600  joules. 

=  857.16  calories. 
=  2654.4  foot-pounds. 
=  366.98   kilogram-me- 
ters. 

1  watt  =  1  joule  per  second. 
"      =  .2381  calorie  per  second. 
=  .73732  foot-pound  per  sec- 
ond. 


1  watt  =  .10194  kilogram-meter  per 
second. 

1  watt  =  .0013406  horse-power. 
"      =  .001  kilowatt. 

1  horse-power  =  745.94  watts. 

=  177.6   calories  per 
second. 

1  horse-power*  =  10656  calories  per 
minute. 

1  horse-power  =  550  foot-pounds  per 
second. 

1  horse-power  =  33000  foot-pounds 
per  minute. 

1  horse-power  =  76.04  kilogram, 
meters  per  sec- 
ond. 

1  horse-power  =  4562.4  kilogram- 
meters  per  min- 
ute. 

1  horse-power  =  .74594  kilowatt. 

1  kilowatt  =  1000  watts. 

"          =  1000  joules  per  second. 
".        =  238.1  calories  per  sec- 
ond. 


1  kilowatt  =  14286      calories 
minute. 


per 


1  kilowatt  =  737.32  foot-pounds  per 
second. 

1  kilowatt  =  44239  foot-pounds  per 
minute. 

1  kilowatt  =  101.94      kilogram-me- 
ters per  second. 

1  kilowatt  --=  6116.4      kilogram-me- 
ters per  minute. 

1  kilowatt  =  1.3406  horse-power. 


262 


APPENDIX 


X.  — HEATS  OF  COMBINATION 

Heats  of  Combination  in  Calories,  for  Equivalent  Weights  in  Grams, 
of  Chlorides,  Bromides,  Iodides,  Sulphate,  and  Nitrates  * 


Element 

Valence 

Chloride 

Bromide 

Iodide 

Sulphate 

Nitrate 

Aluminium    .     . 

3 

53660 

39900 

23463 

25315 

Antimony  .     .     . 

3 

30463 

Bismuth 

3 

30210 

Cadmium  . 

2 

46620 

37600 

24215 

44940 

43000 

Cobalt   .... 

2 

38240 

44350 

42270 

Copper  .... 

1 

32875 

24985 

16260 

Copper  .... 

2 

27980 

26205 

Gold       .... 

3 

7607 

2950 

Hydrogen  .     .     . 

1 

39315 

28380 

13170 

39170 

33830 

Iron  

2 

41025 

46600 

44835 

Lead      .... 

2 

41385 

32225 

19900 

34035 

Magnesium    .    . 

2 

75505 

90090 

88240 

Manganese     .     . 

2 

55995 

60625 

58860 

Mercury     .     .     . 

2 

31580 

17155 

18535 

Nickel  .... 

2 

37265 

43475 

41710 

Silver    .... 

1 

29380 

22700 

13800 

10195 

8390 

Tin    .... 

2 

40395 

Zinc  

2 

48605 

37965 

24615 

53045 

51255 

*  These  values  are  taken  from  Thomsen's  Thermo-chemische  Unter- 
suchungen.  The  sulphates,  nitrates,  and  hydrogen  compounds  are  for 
aqueous  solutions.  The  chorides,  bromides,  and  iodides  are  anhydrous. 


APPENDIX  263 

XL  — SPECIFIC  RESISTANCE  OF  VARIOUS   SUBSTANCES 


Substance 

Temperature 

j*> 

J 

1 

GO 

p 
in  Ohms 

%  Solution 

Observer 

0°C. 

10  6 

.000001500 

Matthiesen 

10.6 

.000001530 

M 

89 

.000001594 

i 

Copper  (hard  drawn)  .... 
Gold  (annealed)  
Gold  (hard  drawn)  
Aluminium  (annealed)  .  .  . 
Platinum  (annealed)  .... 

II 

8.9 
19.3 
19.3 
2.6 
21.2 
8.1 

.000001629 
.000002052 
.000002089 
.000002903 
.000009030 
.000009687 

' 

Tin  (pressed)  .  . 

II 

7  3 

00001317 

t 

Zinc  (pressed)  .  . 

« 

71 

.000005598 

4 

Lead  (pressed)  

II 

11.4 

.00001957 

4 

Nickel  (pressed) 

M 

8.5 

00001242 

j 

German  silver  .  . 

II 

about  .0000209 

4 

Graphite  .  .  . 

(( 

2  3 

0024  to  .042 

Everett 

Retort  carbon 

II 

1  9 

07 

Mercury  

M 

13  6 

000094073* 

Nitric  acid  in  water  

18°  C. 

1.185 

1.28  t 

29.7 

Kohlrausch 

Hydrochloric  acid  in  water     .     . 
Sulphuric  acid  in  water      .     .     . 
Phosphoric  acid  in  water  .     .     . 
Tartaric  acid  in  water   .... 
Acetic  acid  in  water      .... 
Ammonium  chloride  in  water    . 
Sodium  chloride  in  water       .     . 
Sodium  sulphate  in  water      .    . 
Zinc  sulphate  in  water       .    .    . 
Zinc  sulphate  in  water       .    .    . 
Copper  sulphate  in  water  .     .     . 
Potassium  sulphate  in  water 
Potassium  bichromate  in  water- 

n' 

10°  C. 

1.092 
1.224 
1.307 
1.107 
1.022 

1.270 
1.422 
1.205 

1.31  f 
1.36  t 
4.79  t 
9.97  t 
61.9    t 
2.5    t 
4.7    t 
11.3    t 
28.5    t 
33.7    J 
29.3    $ 
16.6    $ 
29,6    J 

18.3 
80.4 
46.8 
22.4 
16.6 

Kohlrausch 
and 
)    Nippoldt 

Ewing 
and 
Macgregor. 

Further  data  on  the  conductivity  of  the  solutions  can  be  found  in 
Physikalisch-Chemische  Tabellen,  Landolt  and  Bornstein,  pp.  103, 
106. 

Kohlrausch  and  Nippoldt,  Pogg.  Ann.,  138,  p.  379  (1869). 

Grotrian  Pogg.  Ann.,  151,  p.  378  (1874). 

Kohlrausch  and  Grotrian,  Pogg.  Ann.,  159,  p.  233  (1876);  and 
Wied.  Ann.,  6,  p.  145  (1879). 

*  From  the  definition  of  the  ohm. 
t  Solution  of  minimum  resistance.  J  Saturated  solution. 


264 


APPENDIX 


XII.  — DENSITIES  OF  VARIOUS   SUBSTANCES 

The  following  table  gives  the  weight  in  grams  of  1  cc.  of 
the  substance.    These  densities  are  but  approximate. 


Acetic  acid 1.064 

Agate 2.615 

Alcohol,  absolute  .  .  .  0.796 
Alcohol,  methyl  .  .  .  .0.796 

Alum 1.724 

Aluminium 2.670 

Amber 1.078 

Antimony,  cast  ....  6.720 
Apple-tree  wood  ....  0.790 

Arsenic '  .     .  8.310 

Ash,  dry 0.690 

Ash,  green 0.760 

Asphalt 2.500 

Basalt 2.950 

Beech,  dry  ...  0.690  to  0.800 

Beeswax 0.964 

Bell-metal 8.050 

Benzine  ....     0.72  to  0.740 

Benzole 0.884 

Birch 0.690 

Bismuth,  cast 9.822 

Blood 1.060 

Boxwood 1.280 

Brass,  cast 8.400 

Brass,  sheet 8.440 

Brick 1.6  to  2.000 

Bromine 3.187 

Butter 0.942 

Calcium  chloride  .     .     ..  2.230 

Camphor 0.988 

Carbon  disulphide  .  .  .  1.272 
Carbon  dioxide,  liquid  .  .  0.947 
Cedar,  American  ....  0.554 

Chalk 1.8  to  2.800 

Cherry-tree 0.710 

Chestnut 0.606 

Chloroform.  .  1.500 


Clay 1.920 

Coal,  anthracite    .     1.26  to  1.800 
Coal,  bituminous  .     1.27  to  1.423 

Cobalt 8.800 

Concrete,  ordinary    .     .     .  1.900 
Concrete,  in  cement  .     .     .  2.200 

Cork 0.240 

Copper,  cast 8.830 

Copper,  sheet 8.878 

Deal,  Norway 0.689 

Diamond 3.530 

Earth       ....     1.52  to  2.000 

Ebony 1.187 

Elder 0.690 

Elm 0.579 

Elm,  Canadian      ....  0.725 

Emerald 2.770 

Emery 3.900 

Ether 0.720 

Feldspar 2.600 

Fir,  spruce 0.512 

Fluorspar 3.200 

Galena 7.580 

German  silver 8.432 

Glass,  flint  .     .     .     .  3.0  to  3.600 

Glass,  crown 2.520 

Glass,  plate 2.760 

Glycerine 1.260 

Gold 19.360 

Gypsum,  crys 2.310 

Granite 2.650 

Graphite 2.500 

Gun-metal 8.561 

Gutta-percha 0.966 

Heavy-spar 4.430 

Honey     .......  1.450 

Human  body 0.890 


APPENDIX 


265 


XII.— DENSITIES   OF   VARIOUS    SUBSTANCES  —Continued 


Hydrochloric  acid,  aq.  sol.    1.222 

Ice 0.917 

Iceland  spar 2.723 

Iron,  bar 7.788 

Iron,  cast 7.230 

Iron,  wrought 7.780 

India-rubber 0.930 

Iodine 4.950 

Iron  pyrites 5.000 

Ivory 1.820 

Lard 0.947 

Lead,  cast 11.360 

Lead,  sheet       ....      11.400 

Lignum  vitse 1.333 

Lime,  quick 0.843 

Limestone 3.180 

Logwood 0.913 

Magnesium 1.750 

Mahogany    .     .     .     0.56  to  0.852 

Maple 0.755 

Marble 2.720 

Mercury 13.596 

Milk -.     .  1.032 

Molasses 1.426 

Mortar,  average    ....  1.700 

Naphtha 0.848 

Nitric  acid  .  .  .  1.38  to  1.559 
Oak,  American  red  .  .  .  0.850 
Oak,  American  white  .  .  0.779 
Oak,  live,  seasoned  .  .  .  1.068 
Oak,  live,  green  ....  1.260 

Oil,  castor 0.970 

Oil,  linseed 0.940 

Oil,  olive 0.915 

Oil,  turpentine      ....  0.870 

Oil,  whale 0.923 

Paraffin  .  .  .  0.824  to  0.940 
Petroleum  .  .  0.836 


Phosphorus  .  . 
Pear-tree  .  .  . 
Pine,  red,  dry  .  . 
Pine,  white,  dry  . 
Pine,  yellow,  dry  . 


.  1,830 
.  0.660 
.  0.590 
.  0.554 
.  0.461 


Pine,  pitch 0.660 

Pitch .     .     .  1.150 

Platinum  wire  ....  21.531 

Poplar,  common   ....  0.389 

Porcelain,  china    ....  2.380 

Potassium 0.865 

Quartz 2.650 

Rock  salt 2.257 

Saltpeter      .     .     .     .     .     .2.100 

Sand,  quartz 2.750 

Sand,  river 1.880 

Sand,  fine 1.520 

Sand,  coarse 1.510 

Silver,  cast  .     .     10.424  to  10.511 

Slate 2.880 

Sodium 0.970 

Steel,  unhammered   .     .     .  7.816 

Sugar,  cane 1.593 

Sulphur,  native     ....  2.033 

Sulphuric  acid 1.840 

Tallow 0.940 

Tar 1.015 

Tin,  cast 7.290 

Tourmaline,  green     .     .     .  3.150 

Vinegar 1.026 

Water,  at  100°  C.       .     .     .  0.958 

Walnut 0.680 

Water,  sea 1.027 

Wax,  white 0.970 

White  metal,  Babbitt     .     .  7.310 

Willow    . 0.585 

Zinc,  cast 7.000 


266  APPENDIX 

XIII. —  TABLE    OF    SOLUBILITIES* 

Showing  the  classes  to  which  the  compounds  of  the  commonly 
occurring  elements  belong  in  respect  to  their  solubility  in  water, 
hydrochloric  acid,  nitric  acid,  or  aqua  regia. 

Preliminary  JRemarks 

For  the  sake  of  brevity,  the  classes  to  which  the  compounds 
belong  are  expressed  by  letters,  as  follows : 

W  or  w,  soluble  in  water. 

A  or  a,  insoluble  in  water,  but  soluble  in  hydrochloric  acid, 
nitric  acid,  or  in  aqua  regia. 

I  or  i,  insoluble  in  water,  hydrochloric  acid,  or  nitric  acid. 

Further,  substances  standing  on  the  border  lines  are  in- 
dicated as  follows : 

W-A  or  w-a,  difficultly  soluble  in  water,  but  soluble  in 
hydrochloric  acid  or  nitric  acid. 

W-I  or  w-i,  difficultly  soluble  in  water,  the  solubility  not 
being  greatly  increased  by  the  addition  of  acids. 

A-I  or  a-i,  insoluble  in  water,  difficultly  soluble  in  acids. 

If  the  behavior  of  a  compound  to  hydrochloric  and  nitric 
acids  is  essentially  different,  this  is  stated  in  the  notes. 

Capital  letters  indicate  common  substances  used  in  the 
arts  and  in  medicine,  while  the  small  letters  are  used  for 
those  less  commonly  occurring.  The  salts  are  generally  con- 
sidered as  normal,  but  basic  and  acid  salts,  as  well  as  double 
salts,  in  case  they  are  important  in  medicine  or  in  the  arts, 
are  referred  to  in  the  notes.  The  small  numbers  in  the 
table  refer  to  notes  on  the  following  pages. 

Notes  to  Table  of  Solubilities 

1.  Potassium  dichromate,  W. 

2.  Potassium  borotartrate,  W. 

3.  Hydrogen  potassium  oxalate,  W. 

4.  Hydrogen  potassium  carbonate,  W. 

*  Taken  from  Wells'  translation  of  the  16th  German  edition  of  Fresenius' 
Qualitative  Analysis. 


APPENDIX 


267 


SOLUBILITY   TABLE 


Potassium 

Sodium 

Ammonium 

Barium 

Strontium 

Calcium 

Magnesium 

Aluminium 

Oxide    .... 

W 

W 

W 

W 

w 

W-A 

A 

A 

Chromate  .     .     . 

W, 

w 

w 

a 

w-a 

w-a 

w 

Sulphate    .     .     . 

^13.15 

W 

"Wt4  20-30 

I 

I 

W-I 

W 

W13.M 

Phosphate      .     . 

W 

W8 

W8-12 

a 

a 

Au 

aJ2 

a 

Borate  .... 

W2 

*• 

W 

a 

a 

a 

w-a 

a 

Oxalate      .    .    . 

W3 

W 

W 

a 

a 

A 

a 

a 

Fluoride    .    .     . 

W 

w 

W 

w-a 

w-a 

A-I 

a-i 

w 

Carbonate       .     . 

W4 

W10 

W 

A 

A 

A 

A 

Silicate  .... 

W 

w 

a 

a 

a 

a 

a-i 

Chloride     .     .     . 

W37 

^35 

W21.38 

W 

W 

W 

W 

w 

Brotnid.6         , 

Hf\f\if\a 

W 

W 

1OU1U6     .... 

Cyanide     .     .     . 

W 

W 

w 

\v-a 

w 

w 

w 

Ferrocyanide 

W 

w 

w 

w-a 

w 

w 

w 

Ferricyanide  .     . 

W 

w 

w 

w 

w 

Thiocyanate  .     . 

W 

w 

W 

w 

w 

w 

w 

Sulphide    .     .     . 

W 

W 

W 

W 

w 

W-A  45 

a 

a 

Nitrate       .     .     . 

W 

W 

W 

W 

W 

w 

w 

w 

Chlorate     .     .     . 

W 

w 

w 

w 

W 

w 

w 

w 

Tartrate     .     .    . 

WB.6.  7.  22  46 

W7 

^6 

a 

a 

A 

w-a 

w 

Citrate  .... 

W 

w 

W 

a 

a 

w-a 

w 

w 

Malate  .... 

W 

w 

W 

w&a 

w 

w-a47 

w 

w 

Succinate  .     .     . 

w 

w 

w 

w-a 

w-a 

w-a 

w 

w-a 

Benzoate   .     .    . 

W 

w 

w 

w 

w 

w 

Salicylate  .     .     . 

w 

W 

W 

w-a 

w-a 

w-a 

w 

Acetate      .    .     . 

W 

W 

W 

W 

w 

W 

w 

W 

Formate    .     .     . 

w 

w 

w 

w 

w 

w 

w 

w 

Arsenite    .    .     . 

W 

w 

w 

a 

a 

a 

a 

Arsenate    .     .     . 

W 

W 

w 

a 

a 

a 

a 

a 

5.  Hydrogen  potassium  tartrate,  W. 

6.  Ammonium  potassium  tartrate,  W. 

7.  Sodium  potassium  tartrate,  W. 

8.  Ammonium  sodium  phosphate,  W. 

9.  Acid  sodium  borate,  W. 

10.  Hydrogen  sodium  carbonate,  W. 

11.  Tricalcium  phosphate,  A. 

12.  Ammonium  magnesium  phosphate,  A. 

13.  Potassium  aluminium  sulphate,  W. 


268  APPENDIX 

SOLUBILITY   TABLE  —  Continued 


Cromium 

| 

55 

Manganese 

•3 

i 

g 

1 

O 

Ferrous 

B 

•E 

£ 

1 
co 

, 

Mercurous 

Oxide 

A&I 

A 

a!7 

A 

A 

a 

A 

a 

AM 

A 

Chromate  .... 

a 

w 

w 

a 

a 

w 

a 

A-I 

a 

Sulphate    .... 

W&I]5 

W 

W 

W 

W 

w*, 

W 

W-A 

A-I 

w-a 

Phosphate      .     .     . 

a 

a 

a 

a 

a 

a 

A 

a 

a 

a 

Borate 

a 

a 

a 

a 

a 

a 

a 

a 

a 

Oxalate      .... 

w-a 

a 

w-a 

a 

a 

a 

8 

a 

a 

a 

Fluoride    .... 

w 

w-a 

a 

w-a 

w-a 

w-a 

w 

w 

a 

Carbonate  .... 

A 

A 

A 

A 

A 

a 

A 

a 

Silicate                .     . 

a 

a 

a 

a 

a 

a 

a 

a 

Chloride     .... 

W&I 

W 

W 

W 

W 

W 

w« 

I 

W-I 

A-I 

Bromide    .... 

w&i 

w 

w 

w 

w 

w 

w 

i 

w-i 

a-i 

Iodide             .    .    . 

W 

w 

<f 

w 

w 

W 

w 

i 

W-A 

A 

Cyanide     .... 

a 

A 

a 

a-i 

a-i 

a-i 

I 

a 

Ferrocyanide      .     . 

A-I 

a 

i 

i 

i 

I 

i 

a 

Ferricyanide       .     . 

a 

i 

i 

i 

I 

w 

i 

w-a 

Thiocyanate  .     .     . 

w 

W 

w 

w 

w 

w 

w 

i 

a 

A 

Sulphide    .... 

a-i 

AH 

A 

Ha 

«19 

A 

a 

•* 

A 

A 

Nitrate      .... 

W 

w 

w 

w 

W 

w 

w 

W 

W 

w» 

Chlorate    .... 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

Tartrate     .... 

w 

a 

w-a 

a 

w 

w-a 

W22 

a 

a 

w-a 

Citrate  

w 

w-a 

a 

w 

w 

w 

W 

a 

a 

a 

Malate 

w 

w 

W 

w—  a 

w-a 

a 

Succinate  .... 

w-a 

w 

w 

w-a 

w-a 

a 

a 

a 

a 

Benzoate   .... 

w 

w 

a 

w-a 

a 

a 

Sa'licylate  .... 

w-a 

w-a 

Acetate      .... 

w 

W 

w 

w 

w 

w 

W 

w 

W2, 

w-a 

Formate    .... 

w 

w 

w 

w 

w 

w 

W 

w 

w-a 

w 

Arsenite    .... 

a 

a 

a 

a 

a 

a 

a 

a 

Arsenate    .... 

a 

a 

a 

a 

a 

a 

a 

a 

a 

a 

14.  Ammonium  aluminium  sulphate,  W. 

15.  Potassium  chromium  sulphate,  W. 

16.  Zinc  sulphide,  as  a  sphalerite,  soluble  in  nitric  acid, 
with  separation  of  sulphur ;  in  hydrochloric  acid  only  upon 
heating. 

17.  Manganese   dioxide,  easily   soluble   in   hydrochloric 
acid ;  insoluble  in  nitric  acid. 

18.  Nickel  sulphide  is  rather  easily  decomposed  by  nitric 
acid ;  very  difficultly  by  hydrochloric  acid. 


APPENDIX 


269 


SOLUBILITY   TABLE  —  Concluded 


Mercuric 

•| 

0 

^3 
3 

5 

Cadmium 

• 

2 
o 
O 

Platinum 

Stannous 

Stannic 

Antimonious 

Oxide  

A 

A 

a 

a 

a 

a&i 

AM 

Chromate      .     .    . 

w-a 

W 

a 

a 

•"42 

a 

Sulphate  .... 

w,7 

Wao 

W 

W 

w 

w 

a 

Phosphate    .    .    . 

a 

a 

a 

a 

a 

w-a 

Borate      .... 

a 

w-a 

a 

Oxalate     .... 

a 

a 

a 

w 

a 

w 

a 

Fluoride  .... 

w-a 

a 

W 

w-a 

w 

w 

w 

Carbonate     .     .     . 

a 

A 

a 

a 

Silicate     .... 

a 

a 

Chloride  ..... 

W28 

W 

W-Agg 

W 

WSH 

W37-38 

W 

W40 

W-A  « 

Bromide  .... 

w 

w 

w-a 

W 

w 

W 

w-a 

Iodide  

A 

W 

a 

W 

a 

j 

w 

w 

w—  a 

Cyanide    .... 

W 

a 

a 

W 

W 

Ferrocyanide    .     . 

1 

w-a 

i 

i 

Ferricyanide     .     . 

i 

Thiocyanate      .    . 

w 

a 

a 

w 

Sulphide  .         .     . 

Aw 

•« 

a 

A  ' 

&3C 

a39 

*41 

a41 

A  M.45 

Nitrate     .          .    . 

W 

W 

W* 

w 

W 

Chlorate   .         .     . 

W 

w 

w 

w 

W 

Tartrate   .         .     . 

a 

W 

a 

w—  a 

a 

1*46 

Citrate     .          .     . 

w-a 

W 

a 

Malate      .         .    . 

w-a 

w 

w 

w 

Succinate          .     . 

w-a 

w 

w 

a 

Benzoate           .     . 

w-a 

a 

w 

Salicylate           .    . 

w 

Acetate    .         .    . 

w 

WM 

w 

w 

w 

w 

Formate  .          .     . 

w 

w 

w 

w 

w 

Arsenite  .          .     . 

a 

A 

a 

Arsenate  .         .     . 

a 

a 

a 

a 

a 

19.  Cobalt  sulphide,  like  nickel  sulphide. 

20.  Ammonium  ferrous  sulphate,  W. 

21.  Ammonium  ferric  chloride,  W. 

22.  Potassium  ferric  tartrate,  W. 

23.  Silver  sulphide,  only  soluble  in  nitric  acid. 

24.  Minium  is  converted  by  hydrochloric  acid  into  lead 
chloride ;  by  nitric  acid  into  soluble  lead  nitrate  and  brown 
lead  peroxide  which  is  insoluble  in  nitric  acid. 

25.  Tribasic  lead  acetate,  W. 


270  APPENDIX 

26.  Mercurius  solubilis  Ifahnemanni,  A. 

27.  Basic  mercuric  sulphate,  A. 

28.  Mercuric  amido-chloride,  A. 

29.  Mercuric  sulphide,  ijot  soluble  in  hydrochloric  acid, 
nor  in  nitric  a,cid,  but  soluble  in  aqua  regia  upon  heating. 

30.  Ammonium  cupric  sulphate,  W. 

31.  Copper  sulphide   is   decomposed  with  difficulty  by 
hydrochloric  acid,  but  easily  by  nitric  acid. 

32.  Basic  cupric  acetate,  partially  soluble  in  water,  and 
completely  in  acids. 

33.  Basic  bismuth  chloride,  A. 

34.  Basic  bismuth  nitrate,  A. 

35.  Sodium  auric  chloride,  W. 

36.  Gold  sulphide  is  not  dissolved  by  hydrochloric  acid, 
nor  by  nitric  acid,  but  it  is  dissolved  by  hot  aqua  regia. 

37.  Potassium  chlorplatinate,  W-I. 

38.  Ammonium  chlorplatinate,  W-I. 

39.  Platinum  sulphide  is  not  attacked  by  hydrochloric 
acid,  is  but  slightly  attacked  by  boiling  nitric  acid  (if  it  has 
been  precipitated  hot),  but  is  dissolved  by  hot  aqua  regia. 

40.  Ammonium  stannic  chloride,  W. 

41.  Stannous  sulphide  and  stannic  sulphide  are  decom- 
posed and  dissolved  by  hot  hydrochloric  acid,  and  are  con- 
verted by  nitric  acid  into  oxide,  which  is  insoluble  in  an 
excess  of   nitric  acid.     Sublimed  stannic  sulphide  is  dis- 
solved only  by  hot  aqua  regia. 

42.  Antimonious  oxide,  soluble  in  hydrochloric  acid,  not 
in  nitric  acid 

43.  Basic  antimonious  chloride,  A. 

44.  Antimony  sulphide  is  completely  dissolved  by  hydro- 
chloric acid,  especially  upon  heating;  it  is  decomposed  by 
nitric  acid,  but  dissolved  only  to  a  slight  degree. 

45.  Calcium  antimony  sulphide,  W-A. 

46.  Potassium  antimony  tartrate,  W. 

47.  Hydrogen  calcium  malate,  W. 


APPENDIX  271 

XIV.—  SOLUTIONS* 
Acids 

Cone.  HCl,  sp.  gr.  1.2,  39  %  HCl  by  weight. 

Dil.  HCl,  3  N,  sp.  gr.  1.05,  10  %  HCl  by  weight. 

Cone.  HNOS,  sp.  gr.  1.42,  70  %  HN03  by  weight. 

Dil  HN03,  3  N,  sp.  gr.  1.10,  10  %  HN03  by  weight. 

Cone.  H2SOt,  sp.  gr.  1.84,  98%  H2S04. 

Dil.  H.2$04,  3  N,  sp.  gr.  1.09,  13%  H2S04. 

Cone.  HF,  40%. 

Acetic  Acid,  2  N,  120  g.  of  glacial  acetic  acid  in  1  liter. 

Tartaric  Acid,  2  N,  150  g.  in  1  liter. 

Aqua  Regia,  1  part  of  cone.  HN03  to  3  parts  cone.  HCl  ; 
to  be  prepared  only  when  needed. 

H2S  gas  is  prepared  by  the  action  of  HCl  (1  :  1)  on  FeS  ; 
the  gas  should  be  washed  by  passing  it  through  water  before 
using. 

Bases 


Cone.  Ammonia,  sp.  gr.  0.90,  28  % 

Dil  Ammonia,  sp.  gr.  0.96,  10  %  NH3. 

Sodium  hydroxide,  NaOH,  4  N. 

As  the  material  used  for  qualitative  purposes  contains 
about  10  %  of  water,  the  amount  needed  for  a  4  N  solution 
will  be  4  x  40  x  -V°  =  177.7  g.  in  1  liter. 

Potassium  hydroxide,  KOH,  4  N. 

The  grade  used  for  analytical  purposes  contains  about 
20  %  water  ;  hence  the  quantity  needed  for  a  4  N  solution 
will  be  4  x  56  x  |  =  280  g.  in  1  liter. 

Barium  hydroxide,  Ba(OH)2,  saturated  solution. 

Calcium  hydroxide,  Ca(OH)2,  saturated  solution. 

*  Taken  from  Baskerville  and  Curtman's  Qualitative  Analysis,  New 
York,  1910. 


272  APPENDIX 


Salts 

Ammonium  acetate,  NH4C2H302.  Add  1000  cc.  of  am- 
monium hydroxide  (sp.  gr.  0.90),  slowly  and  with  constant 
stirring,  to  1250  cc.  of  glacial  acetic  acid. 

Ammonium  carbonate,  (NH4)2C03S04  free.  Dissolve,  with- 
out heating,  192  g.  of  the  powdered  salt  in  a  mixture  of 
80  cc.  of  NH4OH  (sp.  gr.  0.90)  and  500  cc.  of  water.  When 
solution  is  complete,  dilute  to  1  liter.  The  strength  is  ap- 
proximately 4  N. 

Ammonium  chloride,  NH4C1,  4  N.     214  g.  in  1  liter. 

Ammonium  motybdate  solution.  To  a  mixture  of  271  cc. 
of  cold  distilled  water  and  144  cc.  of  NH4OH  (sp.  gr.  0.90), 
add  100  g.  Mo03  and  stir  till  solution  is  complete ;  slowly 
add  this  solution  with  constant  stirring  to  a  mixture  of  489 
cc.  HN03  (sp.  gr.  1.42)  and  1148  cc.  of  water.  Allow  the 
mixture  to  stand  for  24  hours  and  then  decant  the  clear 
liquid  into  a  bottle. 

Ammonium  oxalate,  (NH4)2C204  •  H20.     35.54  g.  in  1  liter. 

Ammonium  sulphide  (colorless),  (NH4)2S.  Saturate  3 
parts  of  NH4OH  with  H2S,  add  2  parts  of  ammonium  hydrox- 
ide, and  dilute  with  an  equal  volume  of  water. 

Ammonium  sulphide  (yellow),  (1ST H^S.,..  Digest  the  color- 
less undiluted  (NH4)2S  with  flowers  of  sulphur  in  the  pro- 
portion of  1  g.  to  the  liter  and  then  dilute  with  an  equal 
volume  of  water. 

Ammonium  sulphate,  (NH4)2S04,  N.    100  g.  in  1  liter. 

Barium  chloride,  BaCl2  •  2  H20,  N.    122.17  g.  in  1  liter. 

Bromine  water,  saturated  solution. 

Calicum  chloride,  CaCl2,  anhydrous,  N.     55.6  g.  in  1  liter. 

Calcium  sulphate,  CaS04  -  2  H20,  saturated  solution. 

Chlorine  water,  saturated  solution. 

Cobalt  nitrate,  Co  (N03)2  •  6  H20,  for  confirmatory  tests  for 
Al  and  Zn.  0.5  g.  in  1  liter. 


APPENDIX  273 

Ferric  alum,  Fe2(S04)3  •  (NH4)2S04  -  24  H2O,  saturated 
solution. 

Ferric  chloride,  FeCl3  •  6  H20,*  2  N.     180  g.  in  1  liter. 

Ferrous  sulphate,  FeS04  •  7  H20.  To  be  prepared  in  small 
amounts  as  needed. 

Hydroclilorplatinic  acid,  H2PtCl6  •  6  H20.     10  %  solution. 

Hydrogen  dioxide,  3%. 

Lead  acetate,  Pb(C2H302)2  •  3  H20,f  N.     189.5  g.  in  1  liter. 

Magnesia  mixture.  Dissolve  110  g.  of  MgCl2  •  6  H20  and 
280  g.  of  NH4C1  in  a  liter  of  distilled  water ;  when  solution 
is  complete,  add  261  cc.  of  ammonium  hydroxide  (sp.  gr. 
0.90),  then  add  enough  water  to  make  the  volume  2  liters. 

Mercuric  chloride,  HgCl2-     Saturated  solution. 

Potassium  acetate,  KC2H302.     Saturated  solution. 

Potassium  chromate,  K2Cr04.  N.     97.3  g.  in  1  liter. 

Potassium  cyanide,  KCN,  N.     65.2  g.  in  1  liter. 

Potassium  dichromate,  K2Cr207,  N.     73.8  g.  in  1  liter. 

Potassium  ferrocyanide,  K4Fe(CN)6,  N.     105.7  g.  in  1  liter. 

T^T 

Potassium  iodide,  KI,  —  •     83.1  g.  in  1  liter. 
J 

Potassium  nitrate.  KN02.     500  g.  in  1  liter. 

Potassium  permanganate,  KMn04,  N.     79.1  g.  in  1  liter. 

Potassium  thiocyanate,  KCNS,  N.     97.2  g.  in  1  liter. 

Silver  nitrate,  AgN03,  — •     42.5  g.  in  1  liter. 

Silver  sulphate,  Ag  S04.     Saturated  solution. 

Sodium  acetate,  NaC2H302,  4  N.     328  g.  in  1  liter. 

Sodium  carbonate,  Na2C03  (dry).    Saturated  solution. 

Sodium  cobaltic  nitrite,  Na3Co(]Sr02)6.  Dissolve  100  g. 
KaN02  in  300  cc.  distilled  water,  slightly  acidify  with  acetic 
acid,  and  then  add  10  g.  of  Co(N03)2  •  6  H20.  Allow  the 
solution  to  stand  for  24  hours  and  filter  if  necessary.  As 
the  solution  does  not  keep  very  well,  only  small  amounts 
should  be  prepared  at  a  time. 

*  Should  contain  a  little  free  HC1.  t  The  solution  should  contain  some 
free  acetic  acid. 


274  APPENDIX 

Sodium  nitroprusside,  Na2FeNO(CN)5  -  2  H20.  10  %  solu- 
tion. 

Sodium  phosphate,  Na2HP04  -  12  H20,  N.    119  g.  in  1  liter. 

Sodium  stannite,  prepared  as  needed  by  adding  to  a  little 
SnCl2  solution  sufficient  NaOH  solution  to  redissolve  the 
precipitate  which  first  forms. 

Sodium  thiosulphate,  Na2S2O3  •  5  H20,  N.    124  g.  in  1  liter. 

Stannic  chloride,  SnCl4,  -^    32.7  g.  in  1  liter. 
Stannous  chloride*  SnCl2  •  2  H20,  ?•    56.5  g.  in  1  liter. 

a 

Stannous  chloride  (for  Bettendorff  Test).  Dissolve  113  g. 
of  SnCl2  •  2  H2O  in  75  cc.  of  cone.  HC1,  and  add  a  few  pieces 
of  C.  P.  tin  foil  and  keep  in  glass  stoppered  bottle. 

Starch  paste.  Prepared  as  needed  by  mixing  about  1  g.  of 
powdered  starch  with  a  little  cold  water  to  form  a  thin  paste 
and  then  adding  it  to  200  cc.  of  boiling  water ;  boil  for  a 
minute,  cool,  and  use.  The  solution  does  not  keep,  owing  to 
the  growth  of  molds.  It  may  be  kept  for  some  time,  how- 
ever, if  a  preservative  such  as  CS2  is  added. 

*  Should  contain  a  little  free  HC1. 


APPENDIX 


275 


XV.  — TABLE  EMPLOYED   IN   THE   PREPARATION   OF 
STANDARD   STOCK   SOLUTIONS* 


Quantity  of 

a» 
s 
g 

Substance 

Formular 
Weight 

Solubility 
of  Salt  in 
100  Pts.  of 
Cold  Water 

Per  Cent 
Metal 

Salt  to  be 
dissolved  in 
1  Liter  to 
give  Strength 
Ice.  =100  ing. 

0 

of  Metal 

I 

AffNOo 

170 

V.  S.f 

63.5 

157 

HgN03.H20  .     .     . 

280 

sol.  in  pres.  of 
HN03 

71.5 

140 

Pb(N08)2     .... 

331 

48 

62.5 

160 

Pb(C2H3O2)2-3H2O. 

379 

46 

54.6 

183 

II 

Hg(N08)2.J(H20)    . 

333 

sol.  in  pres.  of 
HN03 

60 

167 

HffClo 

271 

7.4 

74 

135J 

Bi(N03)3  •  5  H20  .     . 

484 

sol.  in  pres.  of 
HNOS 

43 

233 

Cu(N03)2  •  6  H20      . 

295 

V.  S. 

21.5 

465 

CuCl2  •  2  H20  .     .     . 

170 

120 

37 

270 

CuSo4  .  5  H2O  .     .     . 

249 

40 

25 

400 

Cd(NO3)2.4H2O.     . 

308 

v.  s. 

36 

278 

CdCl2.2H20   .     .    . 

219 

140 

51 

196 

3CdSO4-8H20   .     . 

769 

v.  s. 

43.5 

230 

AS2O3     

198 

4. 

75.5 

(      )5 

Na2HAsO3  .... 

170 

V.  S. 

44 

V        Ji 

227 

Na2HAsO4  -'12  H2O  . 

402 

28 

18.7 

(    )ir 

As205      

230 

150 

65 

153 

SbCl3  

226 

sol.  in  pres.  of 

53 

188 

HC1 

SnCl2-2H20   .     .     . 

225 

V.  S. 

53 

189 

SnCl4-5H2O   .     .     . 

350 

V.  S. 

34 

294 

SnCl4  

260 

V.  S. 

46 

218 

*  Taken  from  Baskerville  and  Curtman's  Qualitative  Chemical  Analysis, 
New  York,  1910. 

t  Very  soluble. 

\  This  amount  readily  dissolves  in  1  liter  of  water  containing  .50  g.  of 
NaCl. 

§  33  g.  in  1  liter  HC1  (1 : 1)  gives  strength  1  cc.  =  25  mg.  As. 
IT  267  g.  in  1  liter  will  give  strength  1  cc.  =  50  mg.  As. 


276 


APPENDIX 


XV.  —  TABLE  EMPLOYED  IN  THE  PREPARATION  OF 
STANDARD   STOCK   SOLUTIONS  —  Continued 


Quantity  of 

Q, 

3 

Substance 

Forrnular 
Weight 

Solubility 
of  Salt  in 
100  Pts.  of 
Cold  Water 

Per  Cent 
Metal 

Salt  to  be 
dissolved  in 
1  Liter  to 
give  Strength 
Ice.  =  1(10  mg. 

o 

of  Metal 

III 

A1.2(S04)3.18H20    . 

666 

107 

8.1 

(       )» 

A1C13-6H20        .     . 

242 

74 

11.1 

(       )t 

A1(N03)3.8H20.     . 

261 

v.  s. 

10.3 

970 

Cr2(S04)3  •  18  H20    . 

716 

v.  s. 

14.6 

690 

K2Cr2(S04)4-24H20 

1000 

20 

5.2 

(      )t 

Cr(N03)3.9H20.     . 

400 

V.  S. 

13 

770 

CrCl3-6H2O    .     .     . 

206.5 

v.  s. 

19.6 

570 

FeS04-7H20  .     .    . 

278 

60 

20 

500 

Fe(N03)3.9H20      . 

404 

v.  s. 

14 

715 

FeCl3-6H2O    .     .     . 

270 

V.  S. 

20.7 

482 

Ni(N03)2-6H20.     . 

291 

50 

20 

500 

NiCl2-6H2O    .     .     . 

238 

V.  S. 

25 

400 

NiS04  •  7  H2O  .     .    . 

280 

106 

21 

475 

Co(NO3)2-6H2O.     . 

291 

V.  S. 

20 

500 

CoCl2-6H2O   .     .     . 

238 

V.  S. 

245 

407 

CoSO4-7H20.    .    . 

281 

50 

21 

475 

MnS04.4H20      .     . 

223 

123 

25 

400 

MnCl2-4H20       .    . 

198 

150 

28 

360 

Mn(NO3)2-<>H2O      . 

287 

v.  s. 

19 

527 

ZnSO4-7H2O.     .     . 

288 

135 

22.5 

445 

Zn(N03)2.OH20      . 

298 

V.  S. 

22 

455 

ZriCl2 

136 

v.  s. 

48 

208 

IV 

BaCl2.2H2O   .     .     . 

244 

41 

56 

179 

Ba(C2H302)2  •  H20   . 

273 

63 

50 

200 

Sr(N0302)2  .  4  H20  . 

284 

40 

31 

324 

Sr(NO3)2     .... 

212 

39 

41.3 

242 

SrCl2-6H2O   .     .     . 

266 

106 

33 

304 

CaCl2      

111 

v.  s. 

36 

278 

Ca(N03)2  •  4  H20      . 

236 

V.  S. 

17 

590 

*620  g.  in  1  liter  will  give  strength  1  cc.  =  50  mg.  Al. 
1 450  g.  in  1  liter  will  give  strength  1  cc.  =  50  mg.  Al. 
j;  192  g.  in  1  liter  will  give  strength  1  cc.  «=  10  mg.  of  Cr. 


APPENDIX 


277 


XV.  — TABLE    EMPLOYED   IN   THE  PREPARATION   OF 
STANDARD   STOCK   SOLUTIONS— Conceded 


Quantity  of 

CM 

3 
0 

Substance 

Formular 
Weight 

Solubility 
of  Salt  in 
100  Pts.  of 
Cold  Water 

Per  Cent. 
Metal 

Salt  to  'be 
dissolved  in 
1  Liter  to 
give  Strength 
Ice.  =  100  rag. 

0 

of  Metal 

V 

MgS04  •  7  H20      .     . 

246 

77 

9.7 

(       )» 

Mg(N03)2  •  6  H20      . 

256.5 

200 

9.4 

1060 

MgCl2  •  6  H20  .     .     . 

203.5 

365 

11.9 

837 

NaCl  . 

58 

35 

40 

250 

Na2HPO4-12H2O    . 

358 

9.3 

13 

(      )t 

NaNOj 

85 

80 

27 

371 

KC1 

75 

32 

52 

192 

KHSO4    

136 

v.  s. 

28.5 

350 

KN03      

101 

31 

39 

257 

NH4C1     

53 

33 

34 

294 

(NH4)2S04  .... 

132 

76 

27.5 

365 

NH4NO3       .... 

80 

200 

22.5 

445 

(NH4)2HP04     .     .     . 

132 

36.5 

27.5 

365 

LiCl    

42 

80 

16.7 

600 

LiNOg     

69 

48 

10 

(      )t 

*  515  g.  in  1  liter  will  give  strength  1  cc.  =  50  mg.  Mg. 
t  77  g.  in  1  liter  will  give  strength  1  cc.  =  10  mg.  Na. 
J  500  g.  in  1  liter  will  give  strength  1  cc.  =  50  mg.  Li. 


278 


APPENDIX 


XVI.— COMPARISON  OF  CALCULATED  AND  OBSERVED 
DECOMPOSITION  VOLTAGES  OF  VARIOUS  AQUEOUS 
SOLUTIONS 


Chloride 

Bromide 

Iodide 

Sulphate 

Nitrate 

Calculated 

1 

Calculated 

1 

Calculated 

Observed 

Calculated 

TS 

• 

1 

O 

Calculated 

1 
o 

1.98 

Magnesium  .    . 
Zinc 

3.28 
2  11 

31 
2.11 
1.9 

1.65 
1.63 

2.56 

1.79 
1.58 

1.07 
1.06 

2.01 
1.25 
1.12 

3.91 
2.31 
1.95 

2.35 
2.03 

3.83 
2.23 
1.87 

Cadmium  .     .     . 

2.03 

Aluminium   . 

2.33 

2.0 

1.74 

1.53 

1.02 

.88 

1.10 

Iron  

1.78 

1.6 

1.30 

.68 

2.03 

1.95 

Cobalt  .... 

1.66 

1.43 

1.05 

.51 

1.91 

1.92 

1.84 

Nickel.    .    .     . 
Tin  

1.62 
1.76 
1.80 

1.33 
1.61 
1.63 

1.40 

.85 
1.30 
1.33 

.87 

.36 
.71 

.83 

1.89 

2.09 

1.81 
1.48 

1.52 

Lead     .... 

Copper  .... 
Silver  .... 

143 

1.28 

1.32 
1.11 

1.09 
.99 

1.02 
.95 

.71 
.60 

.64 
.65 

1.22 
.44 

1.14 
.365 

.36* 

Antimony      .     . 
Bismuth    . 

1.32 
1.31 

1.22 
1.21 

.80 
.92 

.44 
.43 

Hydrogen      .     . 

1.71 

1.31 

1.23 

.94 

.57 

.52 

1.70 

1.67 

1.81 

1.69 

The  observed  decomposition  values  of  the  acids  given 
under  hydrogen,  together  with  many  of  the  sulphates  and 
nitrates,  are  taken  from  LeBlanc's  Electro-Chemistry,  pp. 
247-248.  The  other  observed  values  are  from  Crocker, 
Trans.  Am.  Inst.  E.  E.,  1885,  p  281. 
*  Experiment. 


421  n 


